I, too, suffer from a case of the s***ty-apartment-electric-range and also came down with a nasty bout of the I-am-broke-at-the-moments. Turkey fryer is sort of the assumed next step, but propane can get expensive if you brew frequently and on top of that I am not allowed to have propane on my rental property. Induction place was my next thought, but I could only power 120v and the cheapest one was over $100. Then I found out about heat sticks...
You can build yourself a heat stick for about $30, but you're always flirting with danger when building homemade submersible electronics. I didn't have too much electrical experience before building mine, but I followed some directions I found online to the tee and it is still safely functioning ~10 batches later. I wouldn't go down this road unless you're 100% confident in your work. One mistake could potentially be fatal. (PSA:
*ALWAYS AND ONLY USE A GFCI OUTLET*). That is my safety spiel, proceed at your own risk...
I built two heat sticks (120v, 1500w) for about $50 (I only use one at a time; one for back up). They get my 3 gal batch pre-boil volumes (~5 gal) from mash temps to boil in about 15 minutes with the help of my good-for-nothin' range. I haven't tried it with ~7 gal boil yet for 5 gal batches, but I have a second GFCI outlet in my kitchen and I'd just throw two heat sticks in if one wasn't hacking it. For $50, you are getting a hell of a deal. BUT AGAIN!!!!
This can be DEADLY if built incorrectly. Be Smart. Befriend an electrician -d