I was bored, so put together a little history based on browsing through the sightings thread!
After that SDCC-exclusive Thor started off the "Return of Marvel Legends" in 2011, the regular waves started showing up in early 2012.
In Canada at TRU first for $19.99 CAD:
http://www.actionfigurenews.ca/board...postcount=1097
Then a few months later at Zellers for $17.99:
http://www.actionfigurenews.ca/board...postcount=1314
Then finally Walmart:
http://www.actionfigurenews.ca/board...postcount=1418
There was only 7 waves of ROML from 2012-2013.
Then they started the "Infinite" line look in boxes in early 2014.
The Ultimate Goblin and Mandroid waves did start down at $19.99 CAD when they first started showing up.
Target -
http://www.actionfigurenews.ca/board...postcount=1995
Walmart -
http://www.actionfigurenews.ca/board...postcount=2019
TRU brought them in at $26.99 though:
http://www.actionfigurenews.ca/board...postcount=1972
However they did eventually drop to $24.99 a few months later.
Walmart quickly hopped on with their own price increase to $22.92 -
http://www.actionfigurenews.ca/board...postcount=2204
The other 2 waves of 2014 were only available at TRU (Jubilee and Groot waves).
So for all of 2014, Walmart and Target only had the Goblin and Mandroid waves. (Target did end up getting Groot wave in the new year but by then it didn't matter much anymore - for collectors or for the Target chain).
2015's Allfather wave brought a slight tweak to the box style, along with a tweak to the price:
Walmart $24.92 -
http://www.actionfigurenews.ca/board...postcount=2916
All the Target stores were closed by April 12, 2015.
It wasn't until April 2016 that the $29.99 price jump happened. This is also when EB Games started carrying a lot more figures.
TRU -
http://www.actionfigurenews.ca/board...postcount=3737
Walmart a couple months later -
http://www.actionfigurenews.ca/board...postcount=4025
So we went from $18 in 2012 to $30 in 2016. And that's where it's been ever since. So 4+ years at $30 each.
I wouldn't be surprised to see a price jump in the next year, maybe to $32 or something.