Rewards for good behavior?

My son will be 10 this coming up summer (double digits! oh my!!!) and even though Autism plays a part in his life he is very much an "a-typical" child. I have rejoiced over the simplest of things: He told his first lie! He ate something other than a peanut-butter and jelly sandwich! He talked with me (btw 3 or more sentences in the topic of conversation with him is marvelous!!!)! He rode his first roller coaster! He actually talked to another kid on the playground! Yes I know, you may find this very silly but when a child waits so long before they even say "momma" you remember and rejoice over every thing. 

So now that he is alomost 10 I think he needs to learn responsibility and I need to start teaching him to do chores. So last week we started this routine...He gets a "coin", fake money, for every thing that he completes without complaining. If he complains at all then I take 1 coin away from him. This is not real money and he knows that he can't buy anything with it, other than what I have set up. At "Mom's Super Store" he can buy items like:
1. Go to the park (when it's not planned).
2. Go to McDonald's for ice cream and play on the playground.
3. Stay up for an extra 30 minutes.
4. Mom's homemade ice cream.
5. Have a friend spend the night.
6. Rent a movie.

Of course these are just a few of the things that he can purchase. I want him to not only know that he is "working" for something but that he can reward himself. He gets up to 5 coins a day - no more than five. He can save thiem for bigger items in "Mom's Super Store" or he can purchase them as he wants. He gets rewarded for doing his homework with no complaining or talking back, vacuuming, cleaning his room, emptying the little trash cans, etc. I don't pay for things that he should normally do like brush his teeth, get dressed, etc.

I saw a huge improvement in his attitude last week. He seemed like he really enjoyed being able to have something to do during the day after school. I can't wait for this week to begin. As a parent, I have to teach him responsibility. I do believe that his main job is to be a kid. I don't want to take that away from him that's why there is no more that 5 coins daily, plus weekends are free. I can still take one away for attitude issues, but he doesn't have to work for them on the weekend.

Just a side note: I did coins because I don't believe in giving him real money. First, because I am a stay at home mother so money can be a little tight sometimes. Secondly, I don't really think that he should get paid for doing things that he should do to help out. I never received an allowance when I was a child. I do believe that he should be rewarded with what he wants (i.e. some of the things listed above) for completing what he should. We as adults "reward" ourselves when we feel like we've done a good job. Plus I don't think he should be rewarded with sweets.