Not enough information. Why did you buy a minivan? Do you need it to haul a litter of children? Building supplies? Nobody buys a minivan by accident, especially not a fairly new one. If you have hauling needs, have they changed? Were they not really needs? If you didn't have hauling needs, why did you buy it over something more standard?
If you don't need anything a minivan offers, sure, sell it and buy the cheaper car. 2006 with a hundred on the clock should be okay, probably around equivalent or better mileage with better handling. I haven't heard of them being particularly unreliable, but that's just me, I don't hear much about most cars unless they're great or they suck.