Here are some information regarding hotels. I am too looking for cheap hotel in Doha. After wondering for a while i found QR 180 is the cheapest rate/night. Muntaza plaza is good but price is QR 350/night for single bed. There are also some cheap hotels like Tower hotel(QR 200/night), Diammond(QR 180/night) hotel beside Karwa bus station.Here are some hotels i called for price.

Remal Hotel
Tel: (+974) 444 3482
Fax: (+974) 444 3483
P.O. Box: 7434
Email: remalhotel@gaweb
Price: QR 230/night , 730QR for visa

Golden Hotel
Tel: (+974) 432 3322
Fax: (+974) 432 4422
P.O. Box: 60566
Email: [email protected]
Price:QR 200/night, QR 350 for visa

Shezan Hotel & Restaurant
Tel: (+974) 486 5225
Fax: (+974) 486 5267
P.O. Box: 5616
Email: [email protected]
Price:QR 200/night, NO visa provides

Safeer Hotel
Tel: (+974) 435 3999
Fax: (+974) 435 3888
P.O. Box: 3672
Email: [email protected]
Price:QR250/night, no VISA provides

Qatar International Hotel
Tel: (+974) 436 1222
Fax: (+974) 444 2413
P.O. Box: 2572
Email: [email protected]
price:QR 250/night, QR 200 for visa

New Mashriq Hotel
Tel: (+974) 435 6565
Fax: (+974) 435 6566
P.O. Box: 15207
Email: newmashriq@yahoo
price:QR180/night

Gulf Gate Hotel
Tel: (+974) 437 6151
Fax: (+974) 437 6192
P.O. Box: 37871
Email: [email protected]

Dana Hotel
Tel: (+974) 441 1776
Fax: (+974) 441 0687
P.O. Box: 15207
Email: [email protected]
price:QR 250/night

If you find cheaper hotels than that, please let me know too.
Hope that helps
zoso