Paradise has a nice light blue and a teal.
Wolfe has a great light blue. Both have a sea green that is less than great.
Kryolan Aquacolor comes in every colors, light blue and the teal90 and turquoise TK2.
Most times it is good to get two or three colors for shading and creating depth, sometimes a flat colors works, And sometimes it just works based on the pocketbook!
As for cheap you get what you pay for. Most face and body paints in cake makeup form run pretty close in price. Snazaroo is cheap becasue it has less pigments that any other brand. It's good makeup however, but will wear off and fade in colors sooner than any other.
I'd go with Paradise by Mehron. Nice colors, easy to apply, has good staying power and wears well. A 40 gram cake runs 7.95 to 12.95 depending where you buy. On our eCrater site (and usually in store( it is pretty cheap, in the lower price range, ask and we'll ship cheaper than the priority mail flat rate of about $5. Regular parcel rate can go out at about $3.
Note most all brands of teal leave a residue so you look a bit bruised the next day!