I will pay first
Paying first doesn't exactly make sense for something like this, although I appreciate you trying to be transparent and operate with honesty, there are just too many potential problems that would arise from paying first. If you pay someone prior to them doing the work you're asking, you may find yourself unhappy with the work that has been done and without any recourse, so you will just have to deal with it unless they are willing to redo their work for "free". Unless they are a reputable designer around here I wouldn't expect anything fancy, especially for such a small amount of coin. You get what you pay for, but if you paid someone for this first they may only change the alignment or color-scheme and feel proud of their work.
There are many really good graphic designers, thread designs, etc. around the forum that you could contact and negotiate something that you both would be happy about.
SFR10 seems very active, does certain work for free and I've seen them produce some impressive results. Their thread :
https://bitcointalksearch.org/topic/logo-signature-banner-ads-avatar-free-thread-designing-1136108If you don't like their portfolio, there is an entire thread dedicated to just listing all of the services and their respective categories. Go here :
https://bitcointalksearch.org/topic/overview-of-services-2727673 , then scroll down to "Signature and avatar/logo designs" for your other reputable options.
I would be willing to give it a try, but I think we'd both be unhappy with the outcome, which is why you should definitely contact somebody with more experience (probably expect to pay a little more, too).