There are many guilds of all sizes who don't charge an entry fee - from the very largest down to the very smallest.
You are right to say check out guilds as all are different. Fortunately players have the opportunity to leave guilds, just as guilds have the opportunity to kick players out.
Personally I think that no guild is worth paying 400gc to join and I also think that guilds should be restricted to smaller numbers, to prevent the "entry fee" and to help guildies get to know one another.
I would certainly not stand in the way of a guildie wanting to leave (not that I could stop them!) and would wish them well in their new guild