When my work had me overnight near Mohegan Sun I would go there.
Also took my wife there a few times. It's not bad, nice places to eat, some interesting shops, and gambling is ok.
We normally only spent $20 a piece. One time I tried the card game tables and ended up spending $35 that visit. $20-$35 may not seem much but it does last a while and it's all I really feel comfortable losing. I'd be rather unhappy if I lost $100+.
Edit: If it's your first time. Take in only what you feel you can comfortably lose. Leave all your extra money, credit cards, and checks in the car. Would suck to find out $5,000 later that you're easily addicted to gambling.