If I had 150K I would not buy an existing site unless I knew EXACTLY where and how that site was getting its' traffic. I have several sites worth that much and more in revenue (gross) but would never, ever sell them (the whole network or nothing). Because building up a site to do that kind of volume takes a LOT of work and effort, and any potential buyer would need to know exactly how to keep the traffic/sales flowing otherwise they would just be throwing money away.
Sites do not run themselves, and a site cannot exist on Google traffic alone at that volume of sales (I don't think). In other words, just counting on someone searching for the site via Google and making enough sales to justify the 150k investment is a tough find, if at all.
No, sites need to be "worked" - so if a site needs to be "worked" then work your OWN site. True, it takes time to build and perhaps you want something already producing but finding someone to sell a cash cow like that for less than 2-3 years of income will be a hard find. Good luck tho!
BTW: I would have other suggestions for spending that money. Feel free to send me an ICQ on the subject.
Best of luck!!