Often a cause for vigorous debate, the following policies each have merits and devoted champions. Decide for yourself which best fits your mindset and state of pocket!
This is an easy one! Sometimes a tool is needed for a specific job and then that is it. You may never use it again. Often hiring a tool is a good way to meet this need, but that will not always be cost effective or practical if you are going to need it on an ad hoc basis spread over several weeks.
In this category, tools from the cheaper end of the market can be ideal, since if it gets the job done “well enough” that is what matters. If it lasts longer and comes in handy later, then that is a bonus.
Almost any DIY shop will have a suitable supply of tools. The down side it that the quality of the bought tool compared to a hired one may be inferior since the hire shops will typically buy top end tools, so as to get the best life out of them. Then again at least you know that the tool is new, and won't have been abused by a ham fisted Muppet the week before. The bought tool may also be less comfortable to use, achieve lower standard of results, and take longer. Finally, you need to either store or otherwise dispose of the tool when the job is done.
Don’t dismiss this often overlooked option. Second hand tools are often cheaper than new budget ones. Quality will vary but there is a fair chance you can pick up products from all the categories described here.
Prime buying sources include car boot sales, the tip, local papers, and sometimes second-hand or charity shops, and the modern day equivalent of pawn shops. Obviously one needs to take care with some sources to ensure the tools are not stolen property.
Be wary of very old tools since they may be lacking critical safety features that are standard on current ones. Read the specific guidance on these issues in the Tool Types section.
Sometimes places like hire shops will sell off surplus tools. If you can find one that has not been hammered to the edge of its useful life this can be a way of picking up a top quality tool for not much money.
If you are not sure how much actual use you will make of a particular tool, you can buy one from the budget or mid-range, to see how you get on with it. You may find that your purchase satisfies your need, or it may be a stepping stone to something better. It also means when you do buy “something better” you have a much clearer understanding of what features to look for and which ones can be dismissed as “fluff”.
The budget tool may not offer the reliability and performance of a mid range or better tool. However the price is often such that you can buy more than one of each tool, often for the less than the price of a single better tool. Should a tool fail, you simply discard it and switch to it's replacement, and carry on working. The same policy can actually be applied to any type of tool, in any price range, if it is important that you can carry on working in the event of a break-down.
You can have several tools “on the go at once”. With things like drills this may allow faster work since you will not need to stop to swap between say a drill bit and a screwdriver bit; instead just pick up a different tool.
You need to balance this with the fact that the money spent on two tools may buy one of better quality, which may outlast the two cheaper ones, give better results, and be nicer to use. Also you will need more storage space if you have several of each!.
This is the hardest range to purchase from, because there is a huge choice, and it is not possible to make blanket purchasing decisions based on brand, for example. Each brand will have good and not so good products in this class. Buying from this range is often what the ad-men call an “aspirational purchase” (i.e. you would like something better, but budget dictates you buy something similar but cheaper!).
Mid-range tools are often well suited to the less intensive user and are often more than adequate for many DIY-ers. The results and quality of work that can be produced will often be higher than with lower-end tools, and some after sales service and support should be available. This is often true where the manufacturer sells tools in several ranges (like B&D or Bosch for example).
While typically better than the budget tools, you may still find that the quality, comfort of use, and speed etc., may be lacking.
Sometimes only the best will do. If the work you want to do demands the highest quality of finish, or you want the utmost comfort and ease of use from your tools then this might be the approach for you. You can expect tools in this category to stand up to intensive every day use, even for “trade” purposes. Reliability should also be better than the other groups, and spares and after sales service should be readily available. They are ideally suited to the serious DIY-er, the tradesman and the craftsman. You will be getting the smoothest operation, resulting in good finish and low operator fatigue, with good finesse of control.
If you have a habit of being a bit “heavy handed” with your tools then remember these were designed to be used and abused on building sites!
These tools are going to be more expensive, and are more likely to be stolen if not carefully looked after! Note, also, that although repair services are available there will be down time while the repair is carried out. Also the general falling price of tools can render a top quality tool beyond economic repair simply because the “new model” is half the price.
Sometimes there is just the satisfaction of using and owning “the best”
 “Comfort” in this case meaning a tool which has: Good dust collection; lack of vibration; handles placed just where you need them; and controls falling right under your fingertips; Actions happening smoothly, and without jerks; Lock nuts being winged or knurled and not requiring tools; a noise level that while perhaps not quiet, is not all rattle, squeak and screech; Not needing to use excess force and so on...
Many tools are available from a wide range of sources including the big name DIY shops and catalogue shops like Argos, to the specialised independent tool supplier. A growing market sector is the dedicated “online” seller.
For easy availability of budget and mid-range tools, it is hard to beat the big DIY shops. If you want the best and most knowledgeable advice, and after sales service, you will need usually need to seek out a dedicated tool merchant.
If you are looking for the best possible price, the online shop will often give it to you, although it always pays to shop around.
There are cases where an average quality tool, purchased from an above average retailer, will offer some of the benefits and after sales care that usually only comes with much higher price tools.
Once you have bought and used a few tools, it often becomes apparent that there are several non-obvious factors that ought to be considered when purchasing, rather than just features of the product and its price.
For any given purchase you will need to weigh up these factors, since they may often be different for each tool you buy. Experienced DIY-ers will probably include at least the following: