Where to find cheap 3g modems or budget sim bank?

Question

mobile connection

You need to connect 10-15 SIM cards to the computer in turn to give the Internet in turn.
I looked in the direction of the sim bank, but they are very expensive, on alliexpress simple 3g modems from $ 20, where you can find them for $ 5-7 because you don’t waste time transferring SIM cards from the modem and back. USB HUB + 10 modems just right.