That really sucks, I learned a long time ago, never wait or procrastinate, you see something for sale, or even have to go inquire to see if the owner would sell, do it now, once the deal is done, pay up and remove immediately, this is what happens when you do not.
I'm not even a fan of paying up front, and making arrangements to pick up later, because while its still on the sellers property, it could get sold at a higher price from under you and or how many other scenarios could happen.
I have a plow story too. I always read the CL ads, it pays to do so, different things turn up that you may need or have wanted and the prices are always reasonable and or discounted from new or what it would cost to by new, you just have to look things over and know what you are getting.
I see a 2 bottom 101 Ford plow listed, and I did the same as you, the price was a tad high for the condition, I waited, and actually long enough that it should have been sold, one day I see it re-listed fresh, thinking about my plans for the day and all the rest that would cause me to put it off. I've bought off the seller before too. I decided to call him, did so, was still available, he did drop the price $100 in the re-list, so I said I'd take it and would stop by after work, which I did, had him bring it over, gave him a $10 for gas, as that was sufficient for him. Next day I think it was, we had the local soil test guy out to the other place taking samples of the fields, and he mentioned that he was going to buy this Ford 2 bottom plow that was listed, I did not have the heart to tell him I bought it already. The thing is I know there are a lot of these around, just not here, you just never see these for sale, its a good plow, with coulters, tail wheel, has the trailing adjustment lever, and is manual reset if you trip it. I think it was $250, I just put all new wear parts on it, 'cept moldboards, it does need coulter bearings, they are a little loose, but for about $400 I have a field ready plow of good design, one that you could not buy new at that price, especially with the extra items, seems all the ones I see are bare, and not even trip back, shear bolt protected, and seem to be 3x the cost of rebuilding one like mine.
I could have easily missed out on the deal, without a doubt its just good practice to be of the philosophy, "no time like the present" LOL