I've been a huge ULTA fan for years...I'm a Platinum Rewards member and get free samples all the time! The trick is to wait until they offer some amazing GWP (gift with purchase), which they do frequently, and place your order then. Also look for items that have a bonus gift with purchase and you can double up!
For example, here's my latest haul from ULTA:
The only two things that I actually purchased are the Tarte Brazilliance Self-Tanner and the Miracle Skin Transformer concealer.
I ordered during a 'Free Beauty Bag with $50 purchase' event, AND the Miracle Skin concealer came with a 'Free 3-Piece Flawless Skin Set with any purchase.' Plus their usual small offering of samples that you can choose from. I got 3 little foil packets with the Variety Sampler that I chose.
There are some amazing things that came in the free beauty bag, Ojon hair products, Catwalk dry shampoo, Pacifica Body lotion, and lots more. And even better, I had a 20% off coupon, plus $30 in reward dollars...so my $77 order came to about $30 bucks!