Gunsamerica and gunbroker are like ebay for guns, but you need to know what the average price is for such firearms. But I have bought from both, more so when overseas and about to return home. Please dont forget you will have to add the price of shipping and FFL fees. But since you MAY NOT need to pay tax, sometimes this is a cheaper route to go.
I have used Buds several times as well and been happy. Their price with shipping is VERY hard to beat. However supporting local shops means they get to meet you, know you, and you know them. I now get called by name at many of the shops around here, and have been given some good prices on some firearms. Last was one I put on special order from Springfield armory. Its a baby version of the MC Operator. It was 822 with tax. The next cheapest I could even find it on gunbroker or anywhere for was 1100. I told the guy it was way low you sure, he said, you come here alot, and thats how we roll.