1) My understanding is that Google doesn’t like link buying, but it happens all the time (there is a forum here, and every where else for that purpose). Google runs a very gray line in that they state they are against link buying, but don’t have any issues with websites “accepting a reviewing fee”. Google does know certain websites sell links, about 6 months ago, many top directories had their pageranks set to 0. I don’t think Google penalizes sites for being on directories, if they did, competitors could attack each other by placing each others sites on penalized directories.
2) Bid directories – There are only two advantages that I know of for being in the top spots. The first is that most bid directories give the top spot a sitewide link. The second is if it ranks well for terms in your industry. If it ranks well for casino, poker, bingo, sportsbetting terms and is well search engine optimized, you might make money from the traffic it sends you, especially if you can get away with a cheap bid for a top spot on a sub-page with some traffic. If your on a PR4 page, your on a PR4 page, for pagerank purposes it doesn’t matter.
Be wary of brand new high PR bid directories with strange domain names completely unrelated they tend to be dropped domains and a lot of times they loose all their PR at the next Google update.