Lagarto,
I've always just put down the deposit (used to be $25 but apparently that's gone up) and paid $50-$75 to them whenever I had a few extra bucks until the balance was paid off without any problems. Then, all I have to pay is actual shipping costs at the time when the knife is ready to ship. I've bought four knives from them this way since I started collecting Randalls back in 1999. I still owe them $170 on a Model 16 SP-1 fighter that will be finished in 12 months. That's one of the great things about Randall. By the time they actually get it made, you've had more than enough time to pay it off at your leasure and convenience without putting yourself in a money crunch. The only downside to dealing with Randall is the ever increasing wait time. Back in the 90s you got one of their knives in 18-20 months, now I guess it's a little over four years from date of order. I ordered my Model 16 SP-1 two and one-half years ago and won't get it for another year. I'm sure their business has picked up quite a bit since 9/11 from the spec ops guys placing orders. I know that if you're in the military and furnish them with a copy of your deployment orders to Afghanistan or Iraq, they'll bust their ass to rush your knife order ahead of schedule so you get it before you go, provided you don't wait until the last minute before you call them. I could never afford a Randall 25 years ago when I was in the Army (and that was the ONLY knife to have back then), but if they're willing to do that for the servicemen, I really don't mind waiting a little longer for my knife.
Don