This is such a difficult question to answer because it’s subject to so many variables.
If you are in the market for a new computer, you will notice that there are dozens of models with vastly different prices.
It can be daunting to understand the differences and what paying more really gets you.
In so many fields of life you can choose between brand name and generic and often get as much for your money by not paying for branding.
In the computer world this is occasionally true, but less so. Budget computers are usually those with lower end processors, sometimes dated hardware, and generally less robust parts. If your computer needs are VERY basic; some Word Processing, Email, Web Surfing and the like, these budget computers may well meet your needs, but bear in mind that cheaper hardware won't last as long as more expensive hardware, though as I note later, even expensive hardware will generally not last years and years.
Operating Systems and other software change regularly and demand more processing power, so even a high end computer will outlive its usefulness in a few years.
For some people on a limited budget that makes buying an older used computer that will hopefully last a year at least, two years at best, and meets their needs for that time period can be a better choice. You generally don’t pay tax, and although you pay out more often, it can work out at less over time.
New budget PC @ $600 +tax = $672 - best case scenario 5 years usage = $134 per year
Used PC $150 no tax - best case scenario 18 months usage = $100 per year
It’s a toss up and only you can decide. Sometimes it comes down to how much cash is available at the time you want to make your purchase. If you have to finance a new PC and need to factor in interest costs that will dramatically alter the equation.
In either case, buying new or used, get the advice of someone who understands the specifications and can help you determine the best choice for your needs.
Sadly, many high end PCs, over $1000 and up to $2000 or more, are designed more for what they are capable of doing, and less for longevity. They can accomplish much higher end tasks like 3D gaming and video editing, and can run more demanding programs. With more expensive, and generally higher end parts they can hopefully last a little longer, but unless you need that processing power for the kind of computer tasks you need to accomplish, those few extra months may cost more than you bargain for in the long run.
So in general, don’t pay more in the hopes that it will last longer, only pay more for what it can do.
With so many variables these are all generalizations, some budget computers chug along for years, some high end computer die far more quickly than expected. Also in this generalization I am not factoring in the type of PC; Desktop Towers, Laptops, All-in-Ones, Hybrid Tablet/Laptops etc. Each type will alter the costs one way or another.
Also this mostly applies to Windows PCs as Macs are a whole other subject.
Likely though you will be wanting to update any computer within 5 years or so, simply because the Operating System and any new programs you want to run will demand something more than was available when your PC was purchased.
Since for many of us now use a computer of some type every day, there are few basic pieces of advice I can offer
1 - Pay for, or learn how to do, basic computer maintenance to optimize your PCs lifespan
2 - Start saving for your next computer the day you buy your existing one.
Even $25 per month in a fund for a new computer will add up over time, and make the next purchase more palatable. If possible, add another $10 per month for maintenance and possible parts replacements that can lengthen the time between new PC purchases.
3- Do learn how to do backups. EVERY computer will eventually die. You can replace a computer, and you can replace or upgrade programs, but you can’t replace your personal files, especially photos.
4- When you have to make a purchase, be honest about your computer needs and if possible get advice from a trusted, knowledgeable friend – don’t just rely on the advice of salespersons.