I have a couple of the ideal machines, 55 and 300.  The 300 would be alot like yours.  The problem with the big machines is obvious they take up space and they are heavy 300 to 350 pounds. That said I really like the sliders and I believe they are growing in popularity.

As far as value they just depends on what someone is looking for but somewhere between 300 to 400 dollars for a machine like the one you have would be a reasonable price.  You might find someone who is avid 7 up that would fall in love with the embossing and get a little more but like I said the size of your machine hurts it.

You might watch greed bay for a coin mech.  or someone up here might have one they would be willing to turn loose of...

Yours is missing the coin mech. I have one for sell.

I sent you a PM