I did 99% of my IFR and Single Comm. in a 172N that I bought. I did the single IFR first and then I got ready to take the Comm Checkride and then found a twin to rent, flew it for 10 hours, took the Multi-Comm Checkride in it first (added the approaches to get the multi-ifr) then on the same day flew the 172 for the single Comm Checkride. Of course the single had to come last since it didn't meet the requirements for complex configuration on Comm Initial.
After buying the 172 and since selling it, I pretty much got all of my ratings done in it, minus my private and would never look back on it. I shopped around, found a deal, treated it right, and actually made money on the sale. Being savy and cutting off little potions at a time, all said and done I have around 20k invested in every rating including the SEL-CFI... Aircraft ownership isn't for everyone but if you take your time, properly care for the plane, and roll some lucky dice, it can really pay off.