Bella Thorne's 'Amityville' Contract -- Scare The Crap Outta Me For 3 Grand A Week

Disney star Bella Thorne stands to make a small fortune from her new horror flick, "Amityville" ... but there's one perk even Bella couldn't get from producers -- fresh underwear.

The 16-year-old "Shake It Up" star is shooting the latest reincarnation of "The Amityville Horror" ... and according to her contract -- obtained by TMZ -- she's raking in $3,276 a week.

The contract obviously says producers will provide all costumes for the flick, with one exception -- undergarments ... an essential in a horror film.

But here's the real poop ... Bella gets a series of $25K bonuses if the movie does well -- up to $150K if it passes the $100M mark.

And if there's a sequel -- with 12 Amityville flicks, the odds are good -- she'll collect an additional $125K ... and bonuses of up to $300K.