New front axles (with CV joints) aren't expensive to purchase and install yourself (husband and/or you/family/buddy) and installing brakes and new axles together is a good way to do that. I could probably swap out both axles and do the brakes in a day with some decent tools and I'm just a weekend mechanic at best. You can research cost of parts TO YOU, then see what a shop/dealer charges, then add on what the "book" time for any repairs is (all online). Many places have 100% markup on prices and $140 an hour shop rate NOT broken into 15 minute blocks for you. I checked 2006 Buick Lacrosse axle prices and they seem to be about $60-$80 each. Brake pads aren't much, and even rotors aren't expensive anymore.
If you have done solid basic maintenance over the years the car should be in decent shape, and when you consider the car has been paid off for probably some time it isn't throwing good money after bad IF it has more value per month using it than selling it and paying for a different one even with repairs. Say you have a GM car with a 3.8/3800 V-6 engine, one of the best ever made, it's been maintained and has 138,000 miles on it. Engine is going to be fine for few more years, if transmission was serviced and filter changed than that could be good for a few years too. If you had a pre-2002 Caddy with a Northstar engine I'd be worried about head bolts pulling out from the threads in the aluminum block and causing a head gasket leak, or other cars with other issues. So, depending on your car, it might need a timing belt change per owners manual/real world experience (with an interference engine a belt breaking is a disaster), which takes time and might be a shop job, but again, going in knowing the belt costs $X and the book says Z# of hours, you have some idea what it takes to keep a shop running,people learning skills, and insurance.
The guy fixing your car is getting $16-$22 an hour probably to work on your car. The technician had to take classes and get certified so that is part of the price too.
Not going to comment on the 4 to 1 ratio of cars ...
My son was in a similar situation, he had a 2004 that started to need repairs but was paid for, so he opted to a 2009 with payments and more stuff that can go wrong and new sensors (like wheel air pressure that I ended paying for), just might have been MUCH better to deal with the devil he knew or you know ...