I started with 1x30". It allows to do quite a lot even though it lacks in stability, power and has basically not way to tune things. I am ordering a 2x72" now, but since it is just a hobby - Iwould have had a hard time ordering it 6 months ago when I only decided to give knifemaking a try. So my vote is for 1x30" and get a few good quality belts (Norton Blaze or Sait 7S) and some simple carbon steel and start grinding. Make a few knives and see whether it makes sense to get a proper 2x72" grinder (to my understanding grizzly should be good enough even though there are nicer machines). Should you get that 'proper' grinder the little one will still have its use (e.g. without plate for handle shaping).