No. Please come as you are.
There will more than enough time in the future to figure out what clothing you like and how to create it.
Weekly meetings are free and open to the public. The weekend-type events we have do incur a small entrance fee that can range from $7-$30 depending on how long you will be staying and whether you will be camping or staying in a cabin if available.
One of the things that makes the SCA different from Renaissance Faires is that the SCA is a participatory organization - there is no "audience" and no "performers". Everyone who attends an SCA event becomes both "performer" and "audience" by participating in the activities around them. In the SCA you can learn to dance period dances, do calligraphy and illumination, make and fight in armor, sew period clothing, cook period dishes and do pretty much anything else that was done in middle ages and renaissance periods. What makes the SCA different from a Medieval History Class or Humanities 101 Class is that instead of just reading books about things, you actually do them!