My parents and I followed the "gospel" plan on paying for my mission and college
When I was a teenager (13), I offered to work part time throughout the year until my mission, and save 50% of what I made (10% went to tithing, 5% to fast offering, and I was free to spend the other 35%).
And I offered to work hard in school and get the best academic scholarship I could.
And if that wasn't enough to pay for my mission and college, I asked my parents to make up the difference. They wisely agreed.
That's essentially the gospel - we do the best we can, and the Lord makes up the difference.
It worked great for us. I saved up several thousand dollars - not easy for a teenager to do, especially 30 years ago - and got a full tuition scholarship to BYU.
So my parents had to help a little with my mission and freshman year of BYU, but I never needed a dime from them after I got off my mission. I did work part time 2 of my 3 years at BYU, but those jobs were valuable experiences for me, not negatives that detracted from my college experience.
That won't be the best approach for everyone, but it sure worked great for us.