Expand Inflatable Anal Plug
[AD781 Expand Anal Plug]

Pros: Price, Proportion (thickness/length/base), Easy to use.

Cons: Not very 'pretty', Latex (potential storage and allergy issues).

I've recently been exploring solo anal play and this is my first inflatable. The un-inflated size has good proportions between depth and thickness. The narrow part at the base is slim enough that it's comfortable, but not so much that it feels like nothing. Inflating it while holding it in your hand shows that the balloon doesn't inflate exactly evenly, but I imagine there's not real way around it. Inserted, however, your body more or less controls the shape or evenness of inflation. I didn't feel like the inflated part was going to push the whole thing out, but it definitely left m e feeling 'full'.
I'd definitely recommend this for someone interested in inflatable anal experimentation.