Windows seems to be a lot better for running osbot in terms of memory usage. I would go with the first package, since you most likely won't be needing 32gb of ram. at 16gb you will probably be maxing out your cpu before your ram runs out.
Also, try to negotiate with the host. You need very little storage space/bandwidth. You can get the price significantly lower by asking for a custom plan and saying that you can take the minimum hard disk space/bandwidth ( Most hosts have around 500gb-1tb as the minumum for bandwidth, and for hard disk space even like 5-10gb would be more than enough, but minimum is normally like 250). If you have somebody monitoring the bots 16 hours a day though, with them constantly connected via something like teamviewer or vnc, then you might want to up the bandwidth a bit because I think that could use up a lot.
The dedi I am currently using is http://www.hostingsource.com/services/aff.php?aff=209. I pay 87$ a month for a i7 -3770k (3.5ghz, quad core, with hyperthreading), and 16gb of ram. Only get like 1 tb of bandwidth and 250gb hard disk, which is good. The most bots I've put on it is 25, but I could probably put more.
I don't know if you could get a price like that with them now though, I ordered mine during a double ram deal and negotiated a bit. I was originally getting an i5, but they ran out and gave me an i7 for free. Negotiating with the host can actually save you a lot of money, so I would suggest doing so.
Also, an important note, make sure the host you are signing up with allows you run a botting client on it, there are a lot of companies which will not allow it, and could possibly terminate your services if they find out.