It will also remind them to attend. Small users group dues can be used to cover mailing costs as well as refreshment costs. Group leaders or insiders should NOT user the meetings to try to sell training or services. Wait until you are asked. This helps commit people to attend the meetings, gets them involved in the group and takes some of the burden off the group leaders.
Door prizes are nice.
Don't confine yourself strictly to VectorWorks. Teaching the users things about backup, hardware options, and the rest of what makes a successful computerized office is just as important. We did a bit on backup strategies and several of our members thanked us profusely after their offices were broken into later on. For example, a meeting dealing with three topics ranging from basic to advanced will generate much more success than one aimed at advanced users only. Mary Rushing's North Colorado users' group organized a VectorWorks workshop at a local community college.