Monoprice.com shipping: DHL Saver

$16+taxes+taxes+duty (which probably isn't applicable for anything that Monoprice sells)+line items if you're ordering a bunch of unique products.

Depending on the number of unique items, the weight, and the dollar value, it may be cheaper to ship via USPS.
DHL is the cheapest of the "couriers" in terms of fees.

As a general guideline, if it's light/small/numerous/up to about $100, ship via USPS.
If it's heavy, big, over $100, and there's only one of them, ship via DHL.

USPS is the most expensive on shipping charges, but is usually free when your package is below $100. The technical limit is $40, but through personal experience they waive under $100. If they don't, there's a $10 fee which brings it easily in line with DHL.
DHL is cheaper on shipping charges but there's that $16 fee. They also charge for things like line items so if you're buying 100 different things, each one can cost money for the paperwork.

If it was between DHL and FedEx, I'd take DHL.
FedEx is the same as DHL except more expensive for paperwork. Actual shipping I think is cheaper though.