Both IDPA and IPSC/USPSA have membership fees. Usually, most clubs allow you to shoot your first match without being a member of IDPA or USPSA.
Some local clubs may decide whether to enforce membership in IDPA or not. All IDPA sanctioned matches require membership.
USPSA requires membership.
You will also probably need to be a member of NRA. Most gun clubs have this as a requirement, mainly because it reduces the insurance they have to pay.
As far as joining a gun club and moving in 4 - 6 weeks, depends on the cost of the club membership, how much money you have, etc....
As far as what to look for in a gun club:
#1 Are the members SAFE SHOOTERS... if they're not leave immediately.
#2 Is the club range and equipment well maintained and safe to operate?
#3 How friendly are they? Would you like to spend several hours in all kinds of weather with them...
#4 Are there latrines (bathroom, port-a-pottie) ... or do you have to do a woods walk..
#5 If kids are present, are they allowed to just run around or are they properly supervised and controlled.
The list goes on and on. Set a standard and go for it. If the club doesn't meet your needs go someplace else.
Visit some matches and gun clubs and check it out before you spend your money. Most places are very safe, friendly, and welcome visitors.
Happy Shooting