The MPV was sold with an I4 engine until 1998. Since then, the minivan has had a V6 engine. The first generation models were also sold with a choice of a 4 speed automatic or 5 speed manual transmission. Mazda would eventually realize that minivan buyers weren't interested in a manual transmission, so it was dropped in favor of the automatic transmission in the 2nd generation models.
The second generation ended in 2006 with the introduction of the revamped MPV. The newest model has only I4 engines, although there is an optional turbocharged model.
The trim lines in 2006 included the LX-SV, or base model, which sold for $22,115, the LX, which sold for $22,950, and the top model ES, which sold for $28,515.
These vans are out there on the used car market. As I stated earlier, if you buy a 1999 or older model you are going to be buying a far more primative van than if you buy one of the newer models. Try looking on eBay for some good deals.