I have maintained an account on gunbroker for better than a dozen years. Always had a good experience both buying and selling. Read the terms before hit the bid button, if there is something disagreeable, just go to the next item. Some people price stuff higher than I want to pay, just like here. I choose not to be offended, just taking my money to the next buyer. Never had a problem on either end.
I have had a little bit of problem with some online purchases, not at gunbroker, where people try to charge sales tax. If they are a brick and morter store in my state, they have to collect the tax. If I am in doubt, I ask to see their retail merchants certificate and remind them it is a felony to collect sales tax without a current retail merchants certificate. They usually back down if they are illegitimate.
I have had a little bit of problem with some online purchases, not at gunbroker, where people try to charge sales tax. If they are a brick and morter store in my state, they have to collect the tax. If I am in doubt, I ask to see their retail merchants certificate and remind them it is a felony to collect sales tax without a current retail merchants certificate. They usually back down if they are illegitimate.