I'm assuming you will want an AC/DC charger to plug into household outlets.Cheap and not junk? Well, a person can interpret that in different ways.
For a single output charger, I'd recommend something like an HOTA H6 Pro. Product page is
HERE. Banggood has, or had, a promo price of $79.
If I was a gambling man, then it would be the
HTRC C150
For a battery, a
gets my pick. I run the 4600mAh version in my ET410 and will normally stop my runs after 12 minutes...cells will generally be at/around 3.75v. All depends on driving style and motor.