Friejo,
LFS = Local Fish Store.
This term is applied generically to every place that sells aquarium fish/supplies. LFS range from the conscientious, knowledgeable owner-operated store to the big department stores with some fish dumped into tanks where the only maintenance is to have a teenager skim the dead ones out.
The best advice I can give is to locate all available LFS within your driving area; check them out; then trade with ones you are comfortable with. Getting to know the owner/staff is a real plus for you. I trade with only two in my area, one small, one larger, but both run by the owners. I've gotten to know them and consider them friends outside the buyer-seller association.
I buy everything I can from them, even though I may sometimes pay a bit more than on-line shopping, but I really want my sources to stay in business!! My on-line or mail-order sources are also selected for service and quality and I buy from them, even if another dealer has the same item for a bit less because I want my "good" sources to stay in business too.
Dick
Good customers keep the good guys in business!