Ski Gear

Get two sets of base layers for each family member

Mitt's for kids under 12 are better than gloves.
Dakine mitt's and gloves are a reasonable brand that works well. Make sure they have the little pockets to stuff the "hot hands" heating pads in. I didn't need the pads, but kids liked having them and we changed out to new activated pads every morning.

I tried a Arctix brand bib this year and liked it a lot. Again, reasonably priced and did everything I needed it to do.

Used Back Country a few times to get things.

Back Country

Rent a helmet for sure.

For just about the cost to rent a helmet, you can buy your own.

Outdoor Master Kelvin

For coats and pants, we got alot of gear off of eBay, Facebook Marketplace and a Ski and Snowboard Swap group. Great deals can be found if you're patient.

I got my daughter a pair of Helly Hansen pants for $22, I got a 4 in 1 North Face 550 ski jacket with zip in puffer vest and puffer coat for $135. Found pair of Shady Rays goggles with the magnetic pop on lens with 4 lenses for $60.

As others have said, everyone will need base layers. How many depends on if your accommodations has a washer and dryer.

I would definitely invest in a good par of Smartwool Ski Socks.

Bought my jacket and bibs from Academy in Lafayette a couple of years ago. Ordered the gloves and goggles off of eBay

Skip all of the ski gear packing.
When you arrive at the destination airport, go to the nearest Goodwill.
You will find new (pro ski name brand) ski bibs, jackets, gloves, everything you need.

If there are kid stuff you can’t find, you can always buy there.

It’s what we do every time and saves you a ton on luggage/ baggage fees.

Borrow from someone you know in town. That's the best plan.

Buy them all 2 layers of top and bottom thermals. One to wear and one to wash.
Always wear a helmet. Renting is fine, but if you aren't growing anymore... it's the same price to buy.

Ski gloves, pants, and jackets can be had cheaply.
You can get some cheap goggles for $35 that'll work fine.
Wear Smartwool/equivalent ski socks; the padding helps alot.

If any of them are trying to snowboard (usually takes a whole trip just to learn and you only get to enjoy it the following trip)... get them ski gloves with wrist guards built in. The most common injury when learning is broken wrists.
A pair of crash pads for the butt also helps a bunch when snowboarding because of the sitting and falling on your butt.

I would recommend everyone learn to ski on the first trip. You can do enough to still have fun, and the learning curve to get onto greens and blues and easy blacks is like a day or two.