Eight years ago I bought an excellent used Kirby off CL ($275--divorcee moving from house to an apartment) and gave away my piece of plastic junk that wouldn't clean and would barely run. It was more than the $150 you mentioned, but it was only 2 years old and in near-new condition. The replacement bags are in my cleaning budget, and I have no complaints. It's been great. However, the biggest caveat is the weight. If you're in a two-story house, carrying the beast up and down stairs is cumbersome and possibly a deal breaker for some women.
This machine will outlast me, so even if the price was three times the price of a junker, I'd buy it.
Aside from that, my challenge would be for you to include an emergency fund in your financial planning. You should be able to handle modest household repairs/replacements like this without reaching for credit cards. And even if you have the cash on hand, buy quality. The mustache is about optimizing your dollars and your time. That goal is rarely met by buying the cheapest option available just because it's the cheapest option available. That plan works when the cheapest option available is the BEST option available. Any gains from buying cheap to save on CC's will probably be lost the minute you buy the next replacement vacuum cleaner in two years or less.