How much should I charge monthly for a IT service contract?

I have always dealt in per-visit billing and dont want to sound cheap or a rip-off.

It's a small mortgage office with about 12 pc's and I have made it clear that the only days i'll be servicing them will be on tuesdays and wednsdays.

At first I thought $500 a month but then remembered that the guy I used to work with charged thousands and they seemed to be just fine with that, ok so I'm a solo act and he had 2 people woking for him as sub contractors but still, I was making $1500 bi-weekly.

So that's my question, I dont want to seem unreasonable with a high price or low-rent with a too good of a deal. (also, Im new in the area so I dont have a reputation yet{wich is why my previous boss could charge so much and people wouldnt mind])

Here is the key issue...I have been servicing pc's on the side for the past year..I have recently graduated and have my A+ and Network+ Certifications. Servicing PC's can get detailed especially if you're working on networks. I have several contracts that I currently maintain and I'm employeed full time. Let me just tell you I don't have any contracts under $3000.00 monthly...My suggestion let your work speak for you and you determine the work and what it is worth..

2000 no lower or your done man

I would research other services in the area and see what their going rate is and try to get somewhere in the middle. Being the cheapest isn't always bad as long as you can back it up with decent service