The best place for lipos is hobbyking
Definitely this, no better value exists. And they shift a lot, masses, so the stock is fresh and not “on a shelf for a year”. Can’t help with anything else here though, sorry, my last ground based RC was 30 years ago.
Absolutely do charge & store lipos outdoors (garage/shed) or at the very least on a large inflammable surface with plenty space around and some easy way to get rid if it goes (on a tray you can chuck out the window or something). They don’t go bang very often but when they do they are literally impossible to put out until the lithium is gone and they tend to result in very hot and somewhat expensive fires. RC cars in particular hammer them, physically and electrically, and that increases the chances of blowups. Age (# of uses, as well as calendar age) increases risk as well. Having seen one or two results of lipo fires, they are not pretty. Source – day job involves lipos.
Other opinions available.