if you want sound isolation you should look into iem or canalphones instead of earbuds.
basically this:
earbuds sit on the outside of the ear. this means they have poor isolation and leak sound. they can be a bit uncomfortable since they are normally hard plastic.
canalphones sit inside your ear canal so provide a bit of isolation and do not leak as much sound. i've found these to be comfortable however they tend to fall out with vigorous activity.
iems go deeper in the ear canal and form a very tight seal so are very isolating. not everyone is comfortable with deep in-ear headphones though.
if you want something that stays in your ear even with activity like jogging the ones with bands which go around the ear are nice.
want cheap canalphones which sound good? soundmagic e10s. since it is a canalphone it provides some isolation however not 100%. sound quality is great for the price. you might want to take the advice of some users and use different tips with them though as the included ones might not fit your ears perfect but thats a given for any in-ear.
if you want the best isolation you can get, a deeper in ear IEM would be what you want but you might not be comfortable with how they sit in your ear.