For price of used you can buy new with warranty. BTW the heated gloves do not need a controller. They have three settings you control with a red button on the glove. I believe the controller is discounted when you buy the jacket or pants....-Rich
"IF" you're looking for something NOW, maybe an auto heated seat cushion under your coat will work.
Locally and on sale can be as low as $12.00 One here at EBAY, it's $CH.eap
And "IF" your talented, you might be able to disassemble the pad and resew it into (usually) a vest. BUT!!! Hooking this up to your bike, watch your amps.
There are battery holders that will hold 8 batteries for 12 volts.
Won't last long due to the high power draw.
Maybe, chemical heat packs??? (tho can get expensive)