Alright guys, now I'm really stumped.

As you may recall, I posted a few pages back about possible ignition issues. I thought I had it figured out by changing the battery, It started up easy and I even had it up in the air for a couple of flights. Well I took it back to the field a day or so ago and went to start it up. I started, but had a inconsistinent but definite miss, but that only lasted for a minute before the engine completly quit. I tried starting it for several minutes, but I would not go, so, I pulled the plug out a checked for spark. Out of 100 revolutions there was maybe 5 sparks, so this is seeming like my old issue. Is this sounding like a bad ignition? It is the only thing I think would cause this. Also, if it is the ignition, where can I find the best price on a replacement?