i'm getting a betta on wednesday and wondering what should i look for

i read in a thread on here somewhere that when looking for a betta you should wave your hand over the top of the tank (not in the water!!) and see if he/she responds. They should be aware of their surroundings of they are healthy.
I used that idea when looking for my betta, and it does work. he came up to my finger as if waiting for food to appear!

lol, i try that

Also, lots of people have trouble feeding their bettas pellets etc when they first get them home.
ask the pet shop owner what food the bettas are currently fed, that way you can get something similar, and avoid having trouble feeding a new kind of food to the fish. you can introduce new foods slowly, but keep a fimilar staple diet.

easy!

As with buying any new fish you need to take your time to make sure you get a fish that is as healthy as possible.

When you find one you like the look of you need to do a little inspection of him, this can be hard when they're moving about, but take some time as it is disappointing to get your new fish home and discover something obvious you didn't spot in the store and you don't want a sick Betta to have to treat immediately after getting him home.

Start by looking him over and checking he has all his fins (sounds obvious I know!), two pectoral, two ventrals (the long dangling ones), a dorsal, caudal (tail) and anal fin (the bottom one) Check the fins over for rips, tears and holes. Small pinholes are not uncommon in bettas with very fancy finnage and they can heal up fine. Finnage, depending on the tail type, should generally be long and flowing, except for shorted finned varieties. Avoid a fish with clamped or collapsed fins.

The fish doesn't necesarily have to be absolutely perfect, but as healthy as possible. Look for full rich colours, depending on what colours he is. His body should be smooth and flat with no scales sticking out and no swellings or bloating.

Check he has both eyes and they are clear and not either swollen or protruding or dull and sunken, check they are not cloudy, hazey or whitened.

Look out for any other obvious physicial symptoms like red or blood streaked fins, signs of ick or fungus growth.

He should be active and well balanced when he is swimming about. Like Katmad says, he should be alert and interested and able to swim to the surface of the water. Watch to see that he is breathing normally in the water and from the water surface. Avoid a fish that is constantly flaring or looks like he is really stressed, or "overflared".

There are other things to watch out for but to be honest if you just stand and watch him for a while you will get a pretty good impression as to whether he is healthy or not and all bettas vary so much in personality and behaviour, so he may be very active or less so and still be healthy and well.

Above all, look out for that special Betta that chooses you first. Happy Betta shopping!

I also like to bring a little hand mirror with me and watch to see which betta gets the most excited.

Just look for one that looks healthy, is very active, and doesn't have and missing part or open wounds. If its in a cup the betta should respond if you place your finger next to the cup.