Amazon has Mission Impossible Trilogy on Blu-ray (Mission: Impossible / Mission: Impossible II / Mission: Impossible III) for $17.99 with FREE Super Saver Shipping and $25 purchase. Which makes it less than $6.00 per movie.
Or you can get the Mission Impossible Trilogy on DVD (Mission: Impossible / Mission: Impossible II / Mission: Impossible III)
Pricing was current when the post was published, however Amazon prices change often, so please check before you buy.