I've rocked 6x8 steel side plates before and they're a bit uncomfortable. Just picked up a Strandhogg and I think it runs 6x6". I figure now's a good time to switch over to soft IIIA as I've read a lot of people say they don't really notice it. What do you guys recommend for an inexpensive option? I see those Rhino branded ones on ebay, but I'm not sure if I trust them. Not trying to spend an arm and a leg either. Trying to keep it under $100 if possible, but can stretch a little if I have to.

http://www.skdtac.com/mayflower-cummerbund-armor-inserts-kevlar-p/amr.112.htm

$97 dollars

OP should be prepared for SKD's armor policy though... Read before you buy, If you're not LEO/Mil, at the least you will have to send multiple forms of identification and a signed and notarized affidavit. If the most you will have to have background checks, etc. done in addition to the rest. Velocity makes good stuff though, so if you want to go that route, just ensure you have your ducks in a row in advance.

Bulletproofme.com is also a good choice for new soft armor that you can depend on. (and doesn't have the loops of SKD)

I would be nervous about eBay because on something like kevlar you can't know the condition or that it is even what it says it is. At least when buying through a reputable company you are trusting in a reputable company vs someone on eBay.

KDH side panels from a surplus shop?

I have the Banshee side armor.  $124 for the set IIRC.

I'm having trouble finding the soft side armor on bulletproofme's site. I see the regular hard plates but no soft

Scroll down half way to cummerbund inserts. If they don't have the size you need/want they cut custom sizes too. Call them up and talk to them about what you want, very easy to deal with and very knowledgeable.
http://bulletproofme.com/RP-Backers.html

those are 7x8. well, at least thats what mine are.