My 1996 Bonneville SE, which I think has around 126K miles, died suddenly while I was going up a hill.

I wasn't driving at high RPM, or anything, so i'm not sure what'* wrong.
We were going up the hill, and I turned in the other lane to pass a bus.
When I hit the gas the tachometer went to 3K, then slowly went down. Then the Check Engine light started blinking.
So I pulled in the sunoco [going about 5MPH, because I was afraid to push the engine]

So finally we get to sunoco, I turn the car off and open the hood. Nothing was smoking except for the place where the oil cap was.
It fell off, i'm not sure when, but I'm not sure how bad that is since I didn't have zero oil pressure and my temperature was barely at the 200 mark [I check my gauges a lot]

After we get the oil cap, which fell under the engine, we put it back on and added a bit of oil and tried to start. Nothing.

So after about 40 minutes of trying to start, but no success [and no dead battery, surprisingly] I managed to get it to make a noise. It'* the sound the car makes before the engine actually starts, when the starter'* going but the engine isn't revving.

About 20 minutes after that, we got it to start, and there was white smoke coming very thick from the exhaust, and a little bit coming from the engine. I couldn't tell where from, because the plastic or rubber whatever that covers the engine was blocking. It also sounded pretty bad, not like a grinding really, but nowhere near as smooth as it usually sounds.

So it turns out I had zero coolant. I filled it up, let it sit and tried to start it. Nothing.

So I go back the next day, try to start, and it won't even start to crank. It clicks once, then nothing. I only tried for a minute because it was cold. Today'* the last day I try before I get it towed.

Any ideas on what could be wrong?
I tried to put the 3 things together.
1. Oil cap came off
2. Low coolant
3. Very low RPM

Any thoughts would be great.
And, assuming my engine was completely FCKD, would it be worth buying a new one?
I only paid 1500 for the car at an auction..

My first thought was you got oil on the wires. Make sure the wires are clean. Did you spray oil in the engine compartment? Pull the plugs and inspect. Look for fowling. If your coolant was low, you may have cooked your rings. If it'* not turning over, check the battery. and connections.

Sounds like your UIM may have failed and filled the engine with coolant. Currently it is either dead battery or hydrolocked.

Easy wqy to confirm this is to pull all the plugs and with them out crank it over. If it cranks over and was hydrolocked the engine bay will get blasted with the water from the cylinders.