Using iptel and IPKall, you can receive free phone calls:
First, create a free account at iptel in the form of “user@iptel.org”. Configure your SIP device (mine was Handytone 386) with the IPTel.org login details. Then create a free US inbound number at IPKall with “SIP Phone Number” set as “your_user” and “SIP Proxy” set as “sip.iptel.org”.
Bonus: You can even use this free DID to verify/use a google voice account.