Since you are in RI I have a few places you should check out and compare prices:

Builders Surplus in warwick - there are a few other locations but I have found this location to have the best variety of doors and windows. They pretty much get the oversupply from Home Depot so they can have some good finds.

Home Outlet - there is a location in both east providence and warwick. Most of their stock is available to browse on the website and you can even see if they are clearancing out anything.

The Restore in Charlestown - if your ok with second hand, you can find some great deals here. They will sometimes post what they have on Facebook or Craigslist, but you're usually better off making the drive.

Remodelers Outlet in Fall River - if you're willing to make the drive, this is a great place for doors. They have tons of stock along with returned/uncollected special orders and if they have nothing in your size they can also customize a door for you. We bought a door from them a couple months ago as we had a weirdly sized closet opening and they happened to have a returned door that nearly fit, just had to cut down the height, and it only cost us around $70 if I remember right; over a $100 less than if we had it special ordered from Lowes or HD.