Only cheap if you snipe Craigslist like Chris Kyle going after bad guys and you buy parts off the internet, and most importantly, do every bit of work yourself. Mostly convertibles like this go for twice as much, you need to find someone who actually looks at KBB and doesnt price comparable cars in real life. And the repairs it needs done by a shop would probably run you close to 2 thousand when you add in troubleshooting time and/or tossing parts at problems. Only 200-400 for me because I can troubleshoot and already know a lot about the various failure modes.
The top didnt retract properly once, so they disconnected motors, raised it manually and sold it as "Top not working". After quizzing her, its the tension straps, basically two 4 foot long bungees that run the length of the top and do just that, provide tension. After 18 years, they sort of lose tension. BWM repair is to remove the whole top (10 hours shop labor) replace the tension straps ($250 for those) and reinstall the top ( 15 hours labor) and readjust the top (2 hours more labor). Turns out you can get flat bungee from West Marine, reach in there and install it yourself and do the deal for about $15.
Aux fan not working. If its really the fan and not a $10 relay, BMW part is over $500 dollars. Can get that same part made by VDO, BMWs OEM supplier, off Amazon for $150. Book calls for a lot of disassembly you dont really need to do, making it a four hour job. At $70-$80 an hour shop rates, this stuff adds up quick.