Your calculations seem to be correct, but you are assuming you'll give every user 500 satoshi's, that every user will play 8 times a week, 30 days a month...
In reality, i think the 3000 users will not return each and every day, and make 8 claims a day... Nor will you pay them 500 satoshi's each?
If they do, it would be hard to make +$1000/month with 3k uniques/day