Nina
sorry it took so long to reply.
It depends on what state your in.
I'm in Texas and started out as a reserve officer. The requirements and training are the same for a reserve as they are for a regular. A reserve in Texas has all the same authority as any other peace officer. If you see them on the street, you can't tell the difference.
In Texas, there are several schools that offer academys where you can pay your way through but they are not reserve academys. It takes about 16 weeks to complete and the regular academys are the fastest way to go. I attended a Reserve academy that  is only offered by a law enforcement agency. The standards were the same as the regular academy but the physical training was optional for the most part. Very little agility testing. 
In Texas, the reserve academy is about 700 hours and is done on a part time basis ( because most of the cadetts have full time jobs. They do it in the evenings about 4 days a week and it takes a year to finish the whole thing. But at the end, you are immediately commisioned as an officer with the agency and get your badge and blues. I loved it and did it for about 10 years before going regular. When I decided to go regular, it was a piece of cake.
Hope this helps,  Good luck