I've been to Udon 6 times now and this was my first stay in Udon Cabana, previous stays included Lotus CondHotel, Ruysuk and Top Mansion. I'd thoroughly recommend Udon Cabana. B450 per night which is higher (by roughly 60-100B) than those mentioned, but a month stay works out a B5,900, that's under B200 per night! Rooms are excellent, nice size, very clean, but also very Thai, ie the staff do not talk much English, but you should get buy. Water is included. You pay for electricity only at the end of the month. Inc air con/fridge/TV/Shower/balcony/king size etc.
Has a lift too! Breakfast downstairs before 10am
sa-bai dii reu?