I need help trying to figure out three different movies.
One is a movie about a man and his two kids who own a hotel on the beach or near the beach. The man wants to sell it or close it down until a group of prep school kids show up to stay there for a while. That is about all I remember about the film.

The other movie I only remember is that it involves an alien that came down to conquer earth or hunt another alien. The one alien shoots what appears to compact discs out of his gun.

The last movie all I can remember is that it is about a truck driver and there is something threatening the town that is basically a giant deadly foam or something along those lines. I only remember watching the very end of it.

Maybe your second one is I Come In Peace, aka Dark Angel?

Evil alien: "I come in peace."
Heroic Dolph Lundgren, racking shotgun: "Yeah, and you go in pieces."

Third one has got to be this... Maybe?

The Stuff (1985)

"the Stuff is a malevolent, possibly sentient, natural substance that is trying to take over the minds of the population of Earth"
Miners found the stuff, and it involved a lot of trucks to ship the stuff around. And a tanker scene.

I haven't seen this movie in ages. It's a cool movie.

The first movie is Spring Fling! (1995) (TV)