I don't see anything wrong with you asking for 10% upfront, or them giving you a PO for the total agreed amount. It can be difficult when you want to build up a relationship with them but you also have to get the money in as well. Perhaps an agreement with certain payments that are paid on reaching a certain goal in the project timeline would suit them plus keep the money coming in for you
~M

>I have been doing contract work for over 10 years on an hourly basis. The client's generally pay quickly and it's worked out well for all.
>
>Now I have a new client who wanted a fixed price bid. This is the first of at least 2 projects I'll be doing for them, probably more in the future. This first contract is rather small, and the next one is bigger.
>
>The question is; should I ask for a retainer? If so, how much? If not, how do I ensure that the client won't renege and leave me with nothing to show for it?