McMaster Carr takes credit cards from consumers and has a website.
I purchase from them all the time as they have a distribution warehouse in my area. Shipping is typically next day because of that, and if I really need it, they have a will-call door.
They have an unbelievable array of products and a pretty friendly-to-use online catalog.
Grainger also has a decent amount of products, but they won't sell to consumers, or at least wouldn't last time I checked.