The last time I was in Just About Fish it was a straight salt water only store, no fresh water of any kind. I think you believe your friend so much because he tells you exactly what it is you want to hear rather than the facts. The unfortunate thing is nobody can stop you from abusing your fish the way they can stop you from abusing mammals and birds.
"NOT EVERYONE WHO BUYS A FISH CAN AFFORD TO KEEP IT OR HOUSE IT THEIR WHOLE LIVES ". That statement is exactly true. Thats why responsible aquarists don't buy fish they can't provide suitable housing for throughout their lives. Most of the time you
CANNOT find a home for a fish that has outgrown a tank. That would be like buying a St Bernard puppy for your one bedroom apt., and then taking it to the shelter a year later because you can't take care of it anymore.