First if you worry about cost I would wait until your furbaby is full grown.

If not then a smaller life vest is great. It helps boost there little rumps lol.

We use medium sized just because its hard to find something for their long bodies and for the first purchase take your pup in to try it on first!

We got one for Roxi (outward hound) at REI which is a pretty good one. Has a head floaty and is easy to snap on and off. Has a little more padding then the others I've seen and less gimmicky stuff.

The other one we got (REI was sold out) was from petco and it was just a generic brand called (Paws on Board). Pretty much the same with the velcro and buckles. Didn't have a head rest or as much padding but it fit pretty much the same and helped in the water.

It did loosen up a little faster then the REI branded one though - I did notice that. He slipped out once because I forgot to re-tighten it from the days use b4.

A good test is to hook that puppy up and lift from the back handle to make sure your pup wont slip out but isn't too small to hurt. Of course they all look pretty unhappy when picked up by the handle lol.

I got the paws aboard life jackets and they are great. They are cheaper in price, look around online... I found mine for under $20 and free shipping. Some jackets can be $60 plus and I don't see the need for that since these work perfectly.

My corgis have a med, the dogs are long but any bigger in size wouldn't be tight around their girth area. The straps can be adjusted so they have a good fit, I can pick my dogs up by the handle. The jackets have not moved on the dogs nor have the dogs ever come close to slipping out, just need a good fit. I haven't needed to readjust them.

I posted a pic and you can see my pups swimming. I can post some of them out of the water to if you want.