I hear the Den's sampler
is well worth the 3$, I think they'll refund the $3 on your next order.
It is absolutely worth it. And they refund if your order is above 17$ I think. On my first order it has already been refunded.
My vendor searches showed that a lot of them offer samples. Some have sample sizes of their teas, some have sample packages, some give free samples with every order.
If you'd like to compare whites or oolongs or greens or anything I again would recommend Nothing But Tea. I ordered a sample package of their whites.
TeaChat is a very good source for vendor-addresses. So just give them a try.