I've noticed that amazon has the refills for roughly $25-$30, with free shipping over 25 or 29 (I can't remember).
I did come across a couple of refills that were listed for $60+, but I figured out that if I type "Mr Beer (insert refill name here)" I'll get the cheaper options.
Heck, one guy is selling the Long Play IPA for $90, but when I type "Mr Beer Long Play" into the search I found it for $26.
Hope this helps.
Don’t give up. Make sure you have temp control- ferment at 65F. Add some fresh grains and hops. These three things make all the difference. Tweak to your tastes from there. Stick with it as it is a very rewarding hobby. I understand your frustration. Brew on!