I got my RO off of E-bay. It is a 75GPD unit and only cost me $95. Normally a unit this size runs several hundred dollars.
Trust me, I undertand how the little brats can suck the life right out of your hobby! LOL Good thing they make up for it in other ways!!
You might want to call Culligan and see if they have any rental programs in your area. I know that when I lived in SoCal, Culligan charged me $10 a month to rent an RO unit. They installed it and serviiced it as part of the rental agreement at no extra charge. It only did 10GPD but that's better than nothing...