I don't do very many buyouts in Eve yet because buyouts tend to be capital intensive and can be very risky, especially if you're short on capital to keep buying more as others dump stock. With over 130 billion ISK I might seem rich to many players but I'm really not all that big a market player yet. I'm still relatively new to Eve, some of my competitors have trillions of ISK, huge stockpiles of items and years of experience following long term market trends. Trying to outmaneuver those guys without enough capital for expensive, long, drawn out price wars is a great way to lose a lot of ISK fast. If you don't have plenty of surplus ISK to play with, you have to pick your spots carefully.
When I see a good buyout opportunity that doesn't require too much capital I'll go for it. Recently I noticed someone dumped a huge stack of 900+ Navy Micro Auxiliary Power Cores for a little over 4 million each. Several other sellers undercut him quickly with stacks of 100-200. In a few hours there were close to 2000 for sale, all under 4 million each. I thought about buying them out then but that was an awful lot of stock to move and a fairly large investment. It would take a while to move that many and I wasn't willing to tie up that much capital for very long.
I put up a buy order at around 3.2 mil each and got 50 or so that way. Two or three days later there were 173 left priced under 4 mil each with the next cheapest just under 5 million. I bought all 173 of the cheap ones, giving me 220+ in total. I posted 120 or so for 4,999,997 each on Jita, split the other 100 up and shipped them off to other hubs where I posted them for even more.
The Jita stack didn't get undercut for a least a full day and most of it sold during that time. Over the next few days (after the screenshots above were taken) I got undercut a few times but still sold the entire Jita stack for 4,999,99x ISK each. About half the ones on the other hubs sold in the 6-12 million each range. Those have been undercut a few times since but they're still selling for 5-10 million each.