I/O is an Inboard / Outboard. V-6 or V-8 in the boat, outdrive behind it. Your best bet is going to be a I/O runabout in the 17-21 foot long range. Check out eBay and www.BoatTraderOnline.com
Search your area for runabout brands listed at http://www.monstertower.com/customerphotos/index.htm
. Many great wakeboard boats without the wakeboat price tag.
You dont want a maintenance nightmare so at $4K just be patient and shop for a deal.
If you can find a mid 80's correct craft ski nautique for that your set for quite a while, but they go for $6-10K normally. Just get something reliable, get involved and get on the water. You'll know what you need to do after that :-)