Carl, in all seriousness,
We get requests for quote all the time on the phone. Its pretty easy to sort out the tyre kickers and the price shoppers. For them I have a standard price list, eg "Art is $120 per hour, 200 colour clicks are 55c inc GST". If they are really interested it gets easier after that. If they are not I tell them to go to the opposition and give them the phone number.
For a customer I dont know a 50% deposit to commence work. No money no work. Ive gotten a bit ruthless about it, I do it to major companies as well now. Ive also got a directors guarantee I insist on getting signed before I extend credit to help if things go belly up. The credit worthy dont mind, the objectors are usually trouble, its another sorting mechanism.
I reckon retailers are on to the right idea, you pay and then you get the goods. For those who dont like it tough. Try asking for a 30 day account at Maccas......
Still companies go belly up, my write off this year will be >30K, mostly from companies that have failed, less from thieving rip off artists than last year. I use a Solicitor and have tried recovery agencies (useless as t!ts on a Bull), well published T&C's etc.
I hate bring ripped off! It is personal as well you know. Id rather lose a sale now than be ripped off. When it comes to money humanity is the lowest species on the planet.