Well, my first 10 week class cost $100. And basically classes in my area for almost anything run $10-$15 an hour for a group class.
Books, I have only actually bought two, but the library has a number of them so book costs really should be too high. Also, there's a lot of info on the internet.
Equipment- it depends if you want "offical" equipment or you are willing to settle for "improvised." Jumps can be made out of two stools and a broom stick. Weave poles can be PVC and a metal support bar ($10) stuck into the ground. Tunnels can be found for about $30 at many toy stores (not offical so for big dogs this can be a problem). Contact equipment, if you are handy is basically wood and paint ($100 at most) if you going to do everything yourself. If you are taking classes, really weaves poles were my first purchase and I haven't bought anything else. Pause table, I just use a board on the ground- the idea is the same (wait at a given spot). So, basically, this can be as expensive or as cheap as you want it to be. Oh, and actually, a fenced yard REALLY helps if you are going to practice on your own. You can only get so far on leash.
Entrance fees to shows. In my area I've seen the fee as low as $15 and as high as $25 for the first run each day. They tend to give a price break if you do an additional class (for AKC). NADAC and USDAA are about the same I believe. So, for a weekend of 4 runs (1 JWW and 1 standard each day) you would pay as little as about $50 for the both days or as high as $80 for both days. Some times there is a 3 day event and you pay for another day. It takes 3 legs under 3 different judges (for AKC) to get a title. So, theoretically, you could qualify in one 3 day event. That tends not to happen, but it can.
In my opinion it takes about a year for a novice handler and novice dog to be close to ready to compete. There can be a bit of variation on this, but that's been my expereince as well and many classmates. Once you get experience, that time frame may decrease a bit, but a new dog still needs to understand. Rushing into it doesn't seem to help.
Hope that helps a bit.
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Chelle and the rest of the crew including, but not limited to Kita (the shiba inu), Adi (rescue tabby cat), and all the reptiles