<prompt> Human: I bought the vehicle for 3500, and within three months the engine seized. I had a shop drop in a used engine for another 1800, and quickly found out what 600 worth of labor on an engine swap axtually means. If youre wondering, it means quick and dirty. Real dirty. All in all with minor repairs and the purchase price, Im into the vehicle for about 9k. Already much more than its worth. For the record, yes, I am familiar with the sunk costs fallacy. But I actually really like the vehicle, and I look forward to the prospect of learning how to fix it and keeping it for years. I much prefer funding repair costs and doing the work myself rather than having a lease or loan payment. Currently the vehicle has some as yet undiagnosed issues that Im working through. Theres a major vacuum leak, it needs O2 sensors, and Im sure there are other issues related to intake and exhaust. It may need catalytic converters. Ill figure it out and fix what I can, and pay for what I cant. My Question: In general terms, does it make more sense to buy cheap parts to see if I can get it running? Or should I have faith in my plan, and buy the parts I know Ill want, assuming that eventually the vehicle will be fully repaired again? In specific terms, it needs a new battery. The one in there is 7 years old and no longer holds a charge. Eventually I plan to add lots of auxiliary lights, and maybe Ill add an AC circuit for small appliances. So the question is, do I buy a cheap battery from Walmart for now, or should I dive right into an optima yellow top, knowing that its eventually what Ill want? I can afford either battery, cost isnt the issue necessarily. I just want some insight on how you guys would approach the problem.  <response>: What kind of car is this? 