The cost is about $35 for the water meter. I would also install a shut off valve (about another $8 - $15). You can usually find a handyman to install the water meters from $20 - $40 per meter depending upon quantity. The water meters take from 30 minutes to 1 hour depending upon if the water line is PVC or copper.
You can buy the water meters at Utility Supply Group:
If you buy in bulk they will reduce the price from $35.95 to $32.00. My contact is Wade at 800-800-7082.