Hello there! I know it's already been said, but flexwatt is the way to go.
Here's the most straightforward, easiest tutorial on installing the flexwatt:
http://www.arbreptiles.com/cages/flexwire.shtml
It is IMPORTANT that you use a dimmer, to reduce the risk of fire and to have temperature control! I have had mine on 24/7 with a dimmer and have had no problems.
I just got a cheap thermometer and set it on the flexwatt, when I got it to the temp I wanted it, I 'dotted' a black sharpie dot on the dimmer so I know where to put it if it gets bumped or moved.
You can get all of these supplies from beanfarm, and I recommend them. Here are links to the exact things that I've purchased and currently use with no problem:
http://beanfarm.com/product_info.php?products_id=5569 (You should just need 1ft, but if you plan on expanding or wanting more, I recommend purchasing more than 1ft to save future shipping costs, up to you.)
http://beanfarm.com/product_info.php...oducts_id=5697 (The dimmer switch that I use. I put a dot above the knob, and then adjusted the heat, and dotted the knob to line up with the top for the temp I want to keep.)
http://www.ebay.com/itm/Flex-Watt-he...1#ht_723wt_754 (Here are the clips and plastic protectors for the flexwatt strip.)
You will need an extension chord to give the flexwatt a 'plug'. The above tutorial will be able to shed more light. Also, electrical tape is important too! These are just the supplies that I have used. Feel free to search around online to find things more cheaply or even all through the same seller to save on shipping. Like I said I got my flexwatt a year ago and it's working just as well now as it did the day I got it.
If you're not looking for such a project, just get a plain ol' zoomed mini. Roaches aren't picky, and the hotter the better. My roaches have done well with 85-90F.
Good luck and let me know if I can help!