Does anyone have any suggestions with regards to buying dumbbells in the US?

I’d like to start working out at home some, since I suspect I can do 60-80% of what I do just with dumbbells, but I have no idea where to start finding equipment. Any suggestions of brands, stores or what to watch out for would be appreciated. I definitely need at least 15 lbs (since that's what I curl right now), and I'd like to be able to go heavier for squats and lunges, but I don't know if I should be trying to find weight plates cheap somewhere local, or looking for hex weights, or paying for shipping off the internet.

Thanks!