There are lots of buses daily from Mien Tay bus station in Ho Chi Minh City to My Tho. From here to the centre of town should cost 10,000 to 15,000 dong on a motorbike.
Be aware that when you ask for a ride to the city center from the bus station your motorbike taxi is likely to deliver you to Rang Dong II Hotel which is more than 2 km from the downtown area. It seems they have a business arrangement. To avoid this trap be up front with your motorbike driver about it.
Song Tien - friendly staff and decent rooms. Air-con room including WIFI 300,000 dong.
Minh Quan - Midrange hotel, clean, aircon, wifi, quiet, cable tv, VILF on reception. 550,000 dong.
Minh Tai - Clean, freshly renovated,Fan/Air con 150,000/210,000 dong. Top floor is very breezy so air-con is not required.
Rang Dong - Two locations, stayed at location further from town. Old dingy rooms,dropped here by moto from bus station. Bargained down to 150,000 dong - normal rate 200,000-400,000 dong. Has WIFI but you won't get it in your room (not on top floor lobby either) unless you stay on the lower floors which cost more (and still won't get signal at the ends of the hall).