What do you mean by how do we bid edging? Do you mean how do you include it in a bid with complete lawn care?? Or how to bid a "cut-in" job (which is no fun because you have to come back and scrape it clean with a shovel, etc.)?
McClane makes a great edger for around 300 bucks, Little Wonder makes a good one - a bit more expensive. Brown, now makes an edger for walks and such, and this thing is a monster! It is nothing short of awesome. Here it is. http://www.brownmfgcorp.com/edge/index.html
Hope this helps.