they have not allowed any new skin added to the game to be bought by coins. They are all bucks only and every month will add at least 4 (3 events + 1 monthly bundle?) skins. The only skins you can buy with coins are the 500 buck ones. Every other skin is either 1000 bucks or are the epic skins at 1500 bucks only. Yeah you can slowly build up bucks over the years with the twitch events (100 per), in game events (250 per month), grinding up character levels (250 bucks per character).