Yes, I agree. It depends on what you make, what you use for fabric, and whether you paid full price or bought it either on clearance or by co-op, or repurposed another clothing item to make whatever it is you're making.
I have, in my life, only ever bought one dress off of the rack for formal wear. I have always been rather small in the waist (averaging a 4-6), and rather large in the bust (averaging a DD cup), which makes it difficult to find things that fit both the waist and the bust. PLUS my mother was a master seamstress and we simply could not stomach buying a poorly made dress/gown when we could make it for significantly less (often a half to a third of the cost). For instance, we found the wedding dress I wanted for my wedding in a bridal salon for $2800 (without the slip/head piece/veil, which would have all added another few hundred dollars). My mom made it for $128. My bridesmaids dresses were coutour...I would never have asked them to pay it, but the price tag was over $1200. We made them for $76 per dress, and every single one of them fit like a dream. For a cousin's wedding, I found a dress I loved at the store for $250, and made it for under a hundred.
My daughter is another example. Like an above poster's child, my daughter is very tall and slender for her age. I just made her four "hannah" style play dresses that fit her perfectly...at a size 2/3 for the width of the dress and a seven for the length. I bought most of the fabric on clearance a couple of falls ago, and have been sitting on it for the right project. The last dress I actually made out of organic bamboo (oh my it's so soft!), which I got on sale. I believe I paid less than nine dollars per dress, and then made two pair of crop pants to go under them, for about four dollars a piece. The normal "hannah" price is $38 for the dress and something like $19 for the crop pants. Even Lands End charges $24 for their version of the dress--and neither company has a dress that would not drown my daughter in the width of the dress.
I just made my son six pair of jammy shorts for a grand total of four dollars and ninety cents. Two pair were from mens XL t-shirts that we picked up at the clothes swap last week (a pizza joint shirt and a mission shirt, neither one looks like it was ever worn, and PLENTY of fabric for a pair of knit shorts!), and four from remnants that we picked up the day before yesterday--awesome ones, too! One is a PERFECT fabric for a five year old, with dinosaurs and dinosaur skeletons all over a navy back ground.
The others are a solid grey jersey and a brown waffle knit.
At the end of the swap last week, I was packing up the "plus size ladies" tables, and came across three seer sucker and cotton woven snap up house coats, made of darling fabric. I took them home and have made two pair of crop pants for dd, and will make a skort of the third tomorrow. FREE! AND with the leftover fabric from one of the housecoats, I am actually going to edge some pillow cases to match a quilt that we just received for her as a gift, but that didn't have sheets/pillowcases to match. This fabric coordinates with the quilt as if it was MADE to go with it.
Nothing like repurposing a housecoat!
I don't bother making myself jeans, but will make yoga pants (I can never find them long enough, as I have a 34" inseam) with clearance knit,and will make shorts, especially to work out and knock around the house in...and I always save money on them.
Saving money, I think, though, depends on your building a stash of good fabric that you have looked carefullly for and purchased on clearance or in bulk, or repurposed, and on building a pattern stash and great sewing books on clearance and deep sales. I do always carry my 40% off coupon with me to JoAnns, and always check out the holiday sales if I have any extra cash...and we always check out the remnants bin when we're there, as well, for anything we might find useful.