If you're "poor", you should not get a Mac. Period!
If you have technical know-how, building your own desktop will probably be your cheapest option, while still allowing you to choose quality components.
If you provide your budget, I'm sure people can be of more help to you.
You can build a PC for less than the cost of a new Mac -- but the Mac has much lower TCO (total cost of ownership). This is a common misconception that Windows users have... you guys don't realize how much you have to pay for that we Mac users do not have to pay for.
Microsoft Windows 8.1 Pro -- which still isn't nearly as good as Mavericks -- is $200. Mavericks... is free.
Microsoft Office is now on a subscription model... $100/year. Apple, on the other hand, gives you a copy of Pages, Numbers, and Keynote with a new Mac (and if you have an old Mac you can buy just the component you need for $20, you don't have to buy a "suite") -- upgrades are free (including major version upgrades.) Also identical functionality is provided on the iPad... so I can create a presentation in Keynote on the Mac and give the presentation using the iPad and _all_ features and effects will be identical.
Apple includes other useful software... iPhoto, iMovie (want to shoot videos with your camera and be able to edit them? -- it's included), and Garageband are all free as are the upgrades.
You'll need anti-malware software subscription for a PC -- not for a Mac.
All of that adds up pretty quickly and suddenly the PC isn't so inexpensive anymore. And of course Apple has much better support and odds are if you live anywhere close to a large city there is probably an Apple store near you if you actually need to take the computer in for help.