You know that saying: "You can't judge a book by it's cover"... well, no one really pays attention to that when it comes to events. If your flier looks like shit, you are giving people a bad first impression of your event, and first impressions really do last a lifetime so to speak. You may know a little bit about photoshop and other image editing programs, but unless you are a semi-pro, I would leave it up to the experts. I see way too many events that just seem amateur, and although I may not trip on it too much personally, the people that don't know as much about the music scene as others may be turned away, especially if there is a similar event on the same night that looks a bit more professionally put together.
Clear and vivid imagery is essential, and the font should be something other than a Microsoft Word preset. Dafont.com is where many people go to get free fonts. Your font should also stand out from the background and not just bleed into it, making it difficult to read. I absolutely hate seeing some of the hippie fliers with a cheap stock photo of some computer generated psychedelic crap from 1994, and you can't read a thing.
It is also a bad sign if the text is too close to the edges or too close to other words. There also shouldn't be too much info on the flier, just the most important stuff. I know it can be expensive to get a designer, but if you have the extra $100-$200, it will be a really good investment down the line.
If you have a reoccurring event, maybe you can have the flier designer make a general flier that can just be edited week to week. If they send you the template, all you will really need to change is the DJ lineup and the date. This is one way to save money if you are on a budget. Many people are starting to add QR codes to their fliers as well. I personally think it is ugly, but it is one way to get info to people.