Depending on sun 4/6hrs they could get 5' in 3ys...I would think you could get a 3gal, 18/24" for $35/$40 at a local garden center , the mail are about $30 for a 1 gal

it takes a few years for anabelle to establish so especially if you get a smaller one expect about 3 years for it to get a decent size

It depends on your level of patience and the depth of your pockets. Generally, mine grew fairly quickly from a small plant, as have most hydrangeas in my garden, but YMMV since your growing conditions are most likely fairly different from mine.

also nurseries start discounting plants around now. If you can get one at 50% off may be a good bet.

Mine did not look good (size wise and bloom wise) until year 3.