1996 Plymouth Breeze Car starts but won't Move

Transmission problem
1996 Plymouth Breeze 4 cyl Two Wheel Drive Automatic a lot miles

My friend got a 96 Breeze and the first test drive went okay, but not perfect. It was parked immediately after acquisition. A few days later I noticed some liquid under the car (possibly green). The tires had gone flat. By the time they were replaced, and a new battery put in, the engine would start ok (on the first try) but putting the car into gear and pressing the accelerator, engine revs up, but there is almost no movement from the car. The emergency break seems to be off.

I would like to take it to a proper mechanic, but that would require a tow truck. And if it is a transmission problem, that would be a fair waste of money.

So I would like suggestions on what are the likeliest cause of the problem so I can make a suggestion on whether it is cost effective to take it to the mechanic or just junk it.

The two problems that come my (inexperienced) mine is that either the brake is engaged, and I can't tell, or the transmission is shot. My friend says she has got it to move a bit by pressing down on the gas very hard.

I checked the transmission fluid (using the dip stick), and it is to the appropriate level.