Let's see... on the 88, I recently cracked the block at the track. I bought a used short block for 150$, a head gasket for $8.99 and I still need to buy oil and coolant. So let's say for under 200$, I can get it rolling again.
I would be totally screwed if I couldn't do my own work and diagnosis on my cars. The 97 has actually cost me quite a bit on repairs, however the engine has been flawless (*knocks on wood). I had some issues with the shift forks and had to pay someone else to replace them after pulling the tranny myself. That was quite expensive. The other major cost was the pinion bearing on the rear end. It was a huge PITA to remove the rear end and cost quite a bit to fix it. Otherwise, it has been all relatively small costs for normal wear items... brake pads, tires, struts/shocks, fan motor, wheel bearings, AC parts, ect.
Overeall, I've been very happy with the 97. It is a great daily driver and I always enjoy driving it. However, I'm still pissed that I can't fix the AC correctly. I could rant for a whole page on that.
For the 88, I've had for more than 10 years and spent quite a bit of money, but it is all relatively small costs. I can honestly say that the most expensive single part on that car are the nitto drag radials, at 150$ each. I did pretty much all the work on my own... rebuilt several engines, rebuilt the transmission, ported the head/intake/exhaust... everything.