For that money I'd defo be looking at a quality 2nd hand charger. The LRP Pulsar 1 would be a great charger but difficult to get for theat price I think. The Novak is a good choice because it doesn't discharge or run com lathes etc (it only charges) it's seemed almost low spec these days hence cheap. It's also discontinued which helps the price.
Please don't buy a cheap non adjustable jobbie. Like those ultra budget pro peak ones for example