I think Ring Flashes have a great use for the right subject but, I have found it gives a flat light, which doesn't seem natural. For closeups/macro shots I found better results with simply a low power single flash(some times two) on a bracket with a sync cord. I tend to be anal and take great effort to "standardize" methods. ie-I set up my methods so when most shots end up being say 1:1 (life size) or 1/2 life size I get the same exposure settings. With proper testing you'll find the same exact f/stop is used **every time**, which allows you to concentrate on the subject. Even if it isn't 1:1 with testing you simply reset a useful f/stop. Hey!, it's digital so, just reshoot until its right. Yes? I would bet you could visit most camera stores and find very useable flashes for around $15-$20. You do not need a $200-$500 Macro flash. Because the flash is so close it doesn't need to light the planet. Think about modeling the features of your subject. Think about Portrait lighting. Would on camera direct lighting flatter a face. Mostly not but, some times it works great (maybe 1%). "Things" need to be lit to reveal its shape to make it appear real, natural,just like it's right in front of you.
Drap a white handkerchief over the flash and you'll 1) soften the light 2) cut down the light so you can use a wider f/stop to put near objects out of focus. Be creative, have fun!
FYI I've been involved with photography (earning an income) for over 18 years.Medical photog,expert color printer, advert, wedding, etc on and on.