Buying by case is a very good idea if you can afford; WotC seeds by case. You aren’t guaranteed you’ll have perfect distribution but out of the last dozen cases I’ve seen only two had less than optimal distribution, and even then it wasn’t terrible.
The other major thing about being seeded by case is you occasionally find errors; I had a Pershing that came with a Chi-Ro card, and a Chi-Ro that came with the Pershing card in the same case, but different boosters. Again this isn’t the norm, but it does happen.
I’ve found with cases you generally get 12/15 of the rares, though sometimes a double sneaks in, 2-3 of each uncommon, and 4 of every common. I don’t know if this holds true for Set I as I bought it buy case (hence over a platoon of Tigers, but only a single Panzer II :()
As for the cost it all depends where/how you get it. Some decent deals can be found online, just as long as you make sure they don’t gouge you on shipping. If buying at the FLGS it somewhat depends on just how far you are away from the closest major city… around where I am they cost up to 165$ :x, but once you get into Toronto it drops substantially. I’d say about CD$ 125+Shipping is the range you want to look for… I wouldn’t go for too much more than 150 total.