I understand Captain D's concern about the hygenic issue of rental wet suits.  But if you need to rent a suit make sure it is from a place that you know takes pride in their rental equipment.  At our quarry (Haigh Quarry) we rent all of the equipment a diver would need.   Wet suits in particular are a very popular rental item.  After each wearing we soak the wet suit in a wet suit cleaner and sanitizor. We treat the equipment as if we were going to use it. I certainly don't want to wear someone else's pee-pee suit. So I wouldnt want our customer to wear one either. Many of the renters only dive a few  times a year in our cold water so they feel that the purchase of a wet suit is an unecessary expense.

Personally my first equipment purchase would be a regulator.With my own regulator I would know when it has been serviced and how it breathes.  Remember your life depends on the regulator not the wet suit.