Bike and Part Sales
For bike and part sales you need to make sure you have proper Insurance, and that you are paying the necessary taxes.
Selling Parts
New Parts
Selling parts at distributor (aka wholesale) cost is a bad thing. It undercuts local bike shops, violates your distributor agreement, and if you get caught doing it, it only makes it harder for other community bike shops to get distributor accounts.
Used Parts
Free Ride has a great way of selling parts. They have a color-coded bike that hanging that shows what parts are called and then each parts' bin has a similarly colored part bolted to the front.
Selling Bikes
New Bikes
This is a sticky thing to get into, since it may put you in direct competition with your local bike shop. The shops that seem to do this pick up unique brands that no one else sells, or they specialize in track specific bikes.
Used Bikes
All bikes that you sell should be checked over by a senior mechanic. Not only does this make sure that bikes are in working order but it provides constructive feedback for volunteers and/or staff that are still learning.
Pricing
What can your volunteers/staff handle? If things are always really busy and making change is a hard thing to do, you may want to consider flat rates for all your used parts, like $5 or $10. Keep the nicer parts in a glass case and price them accordingly. New parts have an Manufacturer Suggested Retail Price (MSRP) that you should stick close to so that you don't under cut your local bike shop. A typical MSRP is double the wholesale cost; as an example a $15 wholesale part will MSRP for $30.
Selling parts at distributor (aka wholesale) cost is a bad thing. It undercuts local bike shops, violates your distributor agreement, and if you get caught doing it, it only makes it harder for other community bike shops to get distributor accounts.
Taxes
Generally speaking if your local Salvation Army adds sales tax when they sell used bikes -- your shop needs to as well. If you have a Distributor and are buying new things at wholesale you need to add sales tax because it has never been taxed before. So to recap, everything that is new needs to be taxed, and everything that is used needs to be modeled after your local thrift store.