Best - a nearly-new Ashford Wee Peggy spinning wheel, which I only bought because I thought it was a steal at the price and I thought it was local so could go and pick it up. Turned out to be 300 miles away (Cannington/Callington - doh), but was couriered up no bother. I always expected to sell it on, since it was such a good price, but in fact it's one of my favourite wheels, easy to take out and about, and a very robust easy wheel for beginners to have a go on, so it's stayed.
Best livestock-related purchase - we commissioned an all-terrain tipping hay cradle (takes a big round bale) for the quad bike, from a handy-with-a-welder relative, and it's an absolute godsend. This year especially, as it's been so wet and hence the ground won't take the tractor, and we weren't able to make any small bales. It also has a winch, so you can tip the trailer to upend the bale, take off what you need, then tie the strap around the bale and winch what's left back onto the cradle to take it to the next group.
Best homestead purchase - can't call it between the Rayburn and the all-wool bedding. Would hate to be without either.
Worst is perhaps the locking yoke feed barrier in the main cattle shed. Mainly because we ignored the advice on sizing and 'all or none'. It'd be fine if we had the space it needed to make all the feed spaces the right size, and locking, but as it's only the top end that locks we almost never use it as a locking barrier. The small one, which is as per the advice, for the Jerseys, is ace - although Hillie has now worked out how to release herself, so I have to put a stick through the holes as well for her