It's the same chemical regardless of brand name. GP was clearly pointing out that Sildenafil citrate bought over the counter as Viagra is extremely cheap, not that they gave a baby Viagra.

I think the point was less "haha idiot doctors gave a baby viagra" - it was originally discovered in a search for a treatment for chest pain, after all - and more "wtf viagra doesn't cost that much".

Right, but the point is the cost. Once you know what it is, you can get a mental model of what it usually costs.