Hi. Does felting need to be done with 100% wool, or can it be a wool blend??
Quick answer: No’nYes
Longer answer: It depends. I felted a yarn similar to lionbrands landscape and it felted quite good(though some people seem to have had difficulties with felting it )
If the wool part is bigger than the other than it might felt.
I think if it is a blend, the other fibers need to be natural fibers as well – i.e. alpaca. I don’t think synthetic fibers will felt.
I made my rounds at the “big box” stores today to check out their yarn selections. Wal-Mart, Zellers (in Canada), Michaels…they’re selection of 100% wool was PATHETIC. I found ONE type at Michaels and none at the others. I need to get to our specialty wool store, just haven’t gotten around to it yet. It seemed that all of the blend wools were with acrylic and were specifically marked as machine washable - obviously not usable for felting then. I’ll have to keep looking. I reeeeeally want to make the booga bag.
Seriously, if you don’t mind waiting a few days, order from Knitpicks! You can’t beat the price, great colors, and all orders $30 and up ship free. 
eta…OOPS, not to Canada though. 
I’ve found a lot of good deals on wool at ebay lately…especially if you buy a couple of pounds.