spot on Sam - you can make a rail press for about $35 and use it again and again.
Can you like tell me all the parts you need to make this
Other than that - a couple of spanners, a drill, a 3/8" drill bit, a few screws, and a steady hand! take your time to ensure the whole lot is lined up squarely - once you've got it all assembled, label each end (A and B or however you like) because if you don't you'll soon understand why when it wont go back together the first time you pull it apart!
I used to press 2 sheets of 6mmm ply together at a time rather than stuff around with multiple sheets of 3mm or 4mm and the results were pretty good.