Using the good ol' free Google Keyword Planner is great. But there is an alternate universe of Long Tail keyword phrases that live in Google's other database--namely, their "Autocomplete database." That's the database that is accessed when you're typing queries into the Google search box (notice that list of suggested keywords that pop up as you type?)
I was paid approximately 2/3 of the funds upfront and will receive about 1/3 over the next 2 years. It's now been almost 7 months since we closed the deal, and I've received the first couple of seller financing payments for that final 1/3 on time and am very confident that will continue for the next year and a half until I'm fully paid that final portion.