There are laptop cushions for the wrists that allow the wrists to rest while typing. There are also cooling cushions that go underneath the laptop to prevent your lap from heating up. Check Amazon for a wide selection of cushions at low prices.
From my personal experience a good place to find a used cheap laptop is from any reputable supplier.
You can get a laptop from Circut city,Best buy( if you want to get it for cheap),or any other electronic store.
You can try browsing through the lists of laptops that retailers such as Best Buy have for sale to get a good deal. Generally any laptop from any reliable brand (i.e Acer, Dell, Lenovo, etc.) should be able to do the basics. Just buy a cheap laptop you like with a good warranty.
To find a laptop for cheap you can try looking on EBAY. Be careful to check the sellers feed back and ask any questions before making a bid. There are some companies that sell refurbished laptops on Ebay.
You can use any cleaner on plastic. If you have stains, you can use a little bleach water. If you wanted to, you can even replace the cushions for a whole new look.
I am not sure what your definition of cheap is, but I do not consider any of the less expensive Dell laptops suitable for the games I usually prefer to play.
At the present time cheap laptops are not all that bad. You can get almost any feature you would get on a major laptop. You probably won't get a blu ray player, or HD screen, but everything else including a camera may be there. A good cheap laptop will be from 350-500 dollars. A good deal will have a good amount of memory and any features you would expect.
Pin cushions can be bought from any major retailer that happens to have pin cushions for sale. Pin cushions are useful for any one who needs to pin for cloth down.
Laptops are meant to be small and cheap. As a result, the majority of things in a laptop are also either very small, or software. This makes it nearly impossible to modify a laptop in any way, as parts are made for specific laptops.
No cheap Windows computer will be comparable to an Apple Macbook laptop. Apple does sell the Mac Mini which will do all a Macbook will do and it costs $499. Of course you would need to buy a monitor, keyboard, and mouse. As fas as laptops go it will be very hard to find a cheap laptop that would compare.
You can find a mobile laptop stand that fits directly into any backpack here.http://www.deskspaceanyplace.com/new-order-page-for-model-500.html . They are also pretty cheap.
The windows HP laptop is really small and functional. It's light to carry around and the customer service from Microsoft is very efficient for using it if you have any issues.