my solution is simple, I don't indulge my gun purchasing impulses for long periods of time. My wife and I also do without a lot of things that we consider luxuries at this point, such as having cable tv or a brand new ipad. Our cars are also paid for, so no car payments for either of us. I set aside roughly 30% of our take home pay every month. I now have a decent chunk of cash in our savings account that will serve as our nest egg once our baby is born. My wife will also be on maternity leave for 3 months, so this money will help pay the mortgage and other miscellaneous bills. Sure, I could go out right now and buy several firearms that are on my wishlist and my wife would never know, but our baby comes first, not a gun.
With that said, I still plan on funding any and all firearm purchases with my paypal account. I won't buy what I don't have the money for. I've read far too many foolish stories of individuals who'd rather have that brand new Mossberg 500 rather than pay the rent.