A digital stirring hotplate in decent used condition will set you back about $250. I paid a fraction of that for one with a broken heating function. The problem turned out to be nothing more than a duff switch.
When I ordered some NRF24L01+ boosterpacks from the 43oh store, I asked for a couple of MSP430 Launchpad v1.4 PCBs. These are legacy boards kindly provided by TI (thanks LariSan!) It was fiddly soldering to the tiny 0402 pads since my components were all 0805. The LEDs were especially tricky. But they both turned out OK as you can see. Here they are (alongside a genuine Launchpad on the left) running the breathing LED demo from the OSX Launchpad toolchain.
Exercise bike + magnets + LEDs = festival of light. Devised by T.J.Hunt with specialist engineering expertise from Rabbi Shena Potter Jaffee. Come along 3rd December to the Mayerson Jewish Center of Cincinnati. Pop a beer, grab a latke, and take a spin. Happy Hannukah!