you have 3 types of visit visa,
1- tourist visit, it's for 1 month extendable by another month only.
2- family visit, it's for 6 months max and not extendable beyond that.
3- tourist visit on travel agency, it's for 1 month and not extendable.

cost for 1 and 2 above is QR. 200 per month.
no. 3 is upto the travel agency