My opinion is that if you have to borrow money to buy the plane, don't buy it, because you can't afford to maintain and operate it after you get it. Buy what you can afford - no more.
Lake amphibs are great aircraft for what they were designed for. They are a delight to fly, and handle very well and safely - if flown properly. Training on type (not floatplane training - must be on flying boat, 10 to 25 hours) is vital - you just will not get insurance on a Lake at any price without it! (and you won't get financing without insurance!) If you fly the aircraft without training, your first landing on water will probably be your last. When flown as intended, they are very forgiving, and amazing on the water, but the floatplane landing technique is not the flying boat technique!
As any aircraft does, Lakes do have their limitations, and special maintenance requirements, which you must be aware of. They do a different job than float planes. They are better in some regards, and less sutiable in others. Make arrangements to do a few hours of flying in one before you make your decision. If you seriously need to make it happen, PM me.
As for financing aircraft purchases, I have no idea - I bought my C150 for cash 23 years ago...
Pilot DAR