By the time the chaos came out, power lite had lost its once renowned wings and turned into just another bike brand made from Taiwanese frame sets en-masse and nothing special. There are still a plethora of this era powerlites kicking around complete as generally kids got bought them and hated them. The era when these were being made the BMX had shifted into a more unground movement and the rise of rider owned and made frames were King. Anything mass produced was just for kids whose parents bought it for them as opposed to buying them a mtb like all the other kids had. eBay is the only place you'll get what it's worth. You will see people dressing these up on Facebook like they're made of gold and worth hundreds unfortunately they can say it all they like and they don't sell unless some poor new guy falls for it only to be told later his 300 BMX is worth 50 quid.
Bh were a low end BMX brand known for using cottered cranks and pinched tube dropouts and made from pig iron with a very short top tube making riding them as a grown up somewhat uncomfortable. Sold on garage forecourts, woolworths and mail order catalogues. They're pretty cool in original spec and fit a window in a few peoples BMX lives. Like the chaos there are still loads about being ridden I can think of at least 8 people with them off the top of my head. As for value, they can be picked up complete for as little as £35 and if clean and tidy no more than £100.
Hope this helps.