[Edi]

There's a wide variety on the quality of things you can summon by entering sites. The Bowl of the Lost gives you free banes, while some sites give you free soulless or similar crap that only has a use as a meat shield for taking a couple of missile volleys. The Jungle Temple gives you free lamias, a couple of places give draconians and so forth, but most summon sites are either soulless, ghouls or longdead.

You can see what and how much you can summon for free from certain sites by consulting the magic site DB (downloadable from Arryn's site).

Edi