In theory, reserves do not pay for member travel to the unit for drill.
They do pay travel from home of record to other locations where drill will be performed on a TDY basis. They also pay for travel to the unit for AT or other types of (non-drill) active duty.
Not sure about the USAF, but some specific Navy units have been authorized and funded to pay for member travel to drill as a recruiting/retention tool for critical skills (special warfare/special operations divers are the only ones I'm aware of).