It's a lot cheaper to just buy direct from Asia.
Some distributors have a US warehouse they can ship from if it's in stock, but the only advantage is faster shipping.
You may have local B&M "hobby shops" nearby, but they will have very limited selection.
Best is to determine exactly what you want, then ask the best source for US members.
If you want effective warranty service you will likely have to pay a premium.
Best not to shop on price anyway, lots of counterfeits, scamming sellers.
eBay is great for buyer protection, but also look for vendors with high volume and ratings.