It can cost anywhere from $0 (if you're comfortable with doing it yourself) to $1,000 or more, depending on the level of upgrade and the type of computer. For example, if you want to upgrade your computer's processor, you'll probably have to buy a new motherboard and/or memory as well. If you want to upgrade your computer's graphics card, you may also need a new power supply. And so on. The good news is that there are plenty of resources available online (including this one) that can help walk you through the process of upgrading your computer. So it doesn't have to be expensive or complicated.

The cost of upgrading a computer depends on the hardware and software that you need. Generally, the more expensive the components, the higher the cost of the upgrade. For example, if you want to upgrade your computer's memory, you can expect to pay around $40 for a 4GB module. However, if you want to upgrade your computer's processor, you could end up spending hundreds of dollars. So it really depends on what components you're looking to upgrade and how much money you're willing to spend.