There's no need to pay money to unlock most Huawei USB sticks. Here's a link to a free unlock code calculator. I used it to unlock my E1550.
Yobb GSM Blog: Free Huawei Calculator!
1. Type your IMEI number into the calculator.
2. Generate a NCK unlock code.
3. Insert a "foreign" SIM into your locked USB stick. ("Foreign" means from any carrier other than the one to which the stick is locked.)
4. Start Huawei's generic Mobile Partner software.
5. At the prompt type in the unlock code.