sigh... noob tank
sekito's aren't bad. not great, but not bad either.
however your stinger will shoot better (farther) with heavier weight bb's. .25 or .28. you can find madbull's locally for cheap, or bb bastards which are more expensive. bastards are top quality, but if you're shooting shooting clearsoft crap i would think it's okay to cheap out on bb's.
if you decide to stick with the sport and buy some real guns you'll want to use bastards. but be warned, like many things in life, airsoft isn't cheap.
be safe, use eye protection, don't brandish/shoot in public areas, yada yada...