Guaranteed approval- what a deal!

This isn't a financial blog by any means.  But pretend it is for one minute while I share a little something, okay?
Right after Lexi was born we bought a used Ford Taurus, up until that point we had been driving a two door Hyundai accent, the car seat fit ok in the middle, but we were ready for a little more space, getting that infant seat in the back was a bit of a challenge. We started to think about looking for a car, we had no money saved for a down payment, not great credit and we were still paying on the accent.  Then the middle seat belt broke and we couldn't put her car seat in there anymore, so we put her behind me in the passenger seat and I ate my knees while we went to look at some cars.
We wanted something bigger, but were not ready for a minivan. Looking back now I wish we would have just got one then, but hindsight is 20/20.  We knew what monthly payment our "budget" would allow and were stupid enough to only talk monthly payment not APR. With bad credit, and having to add the amount we still owed on the Accent onto our loan we ended up with a monthly payment that fit nicely, but an APR of around 20%. HORRIBLE.   Once we started getting a little wiser we started working on paying off the car, we ended up paying it off two years early.  In the time that we were working on paying it off we added Caylee to our family. The car started getting small. We could squeeze a small person between the car seats in the back, and going on vacations was a mess, our car was stuffed from door to door, floor to ceiling.  Now we have Josiah too. the three car seats barely fit in the back seat, I'm not even sure they are installed properly because there's no room to get around them to check. We've been on one small trip, but we didn't have to bring half of what we normally do, I have no clue how we're going to make any trips if we don't get a mini van.
Some friends of ours sold us a big GMC conversion van for really cheap, but we've yet to get it on the road and don't think we really want to. We know it will suck the gas so we wont be able to afford to go anywhere. We've been talking up plans as to how to go about wisely buying a van.  We can't really afford monthly payments, but we figured if we could sell our car and the van we could easily afford an older used van.
Today we stopped by a small dealership we drive by a lot because we saw they had a minivan there. The owner came out to talk to us as I was peeking in the windows.  He asked us if we were looking to pay cash or get a loan.  We told him we were thinking about using the credit union that my husband 's work offers. He then told us a price. but not before telling us a little something.
The price if we were going to get financed through him was in the  $9,500 range. With our own financing or cash.... $5,500.  That's right, $4k less. He said the financing company takes so much he has to charge way more in order to make money.  So be careful when car shopping, a guaranteed approval might cost you $4,000!!!
I'd like to see the money that finance company is making, maybe I should try to get one of their accounting jobs!