With power supplies, you pretty much get what you pay for. There are a number of things that differentiate good power supplies from weak links. Rather than impressing you with my ignorance on the subject, give this a read:
Power Supply Information and Selection
Everybody has their own favorite brands which have served them well. Mine are Corsair, Seasonic (makes Corsair PSUs), Antec and PC Power and Cooling. I have no experience with Thermaltake or Silverstone, but they consistently get good reviews. I'm sure I'm omitting several other quality makers.
In short, if you are buying a $65/$75 case and power supply, you are getting a power supply that the manufacturer can afford to throw in that deal. Truthfully, I'd be skeptical of a power supply costing $65 by itself.
One final note on the subject. Usually, when a motherboard, hard drive, video card or memory gives up the ghost, it does so without taking other components with it. Data may be lost, but generally the other components survive. However, it is not unusual for a power supply to go down for the count and take something else with it. Sometimes more than one something else. It is not worth the risk, IMO.