How to build a cheap screen door?

visit a hardware store for 1 x 2 wood, get some nails , get insect screen . some assembly needed

Check out Habitat for Humanity and see if They have some inexpensive doors. Or look for the hanging screens with the magnets . Cost is about $20 and they keep out the flies and bugs just as well as anything else .

The question indicates the doorways requiring screens are on a trailer. Since the entry doors of a trailer open outward, suggest considering using one of the new magnetic mesh screen covering for each of the doorways. They come in different sizes and are easy to secure over the opening using velcro attachments. The prices also differ widely, so shop around. http://www.yourstoreonline.net/magnetic_mesh_screen_door/id2040659/product.html?scomp=googleshopping&gclid=clr51ranqb4cfafdmgod9nia1g http://www.target.com/p/as-seen-on-tv-magic-mesh-brown/-/A-14048570?ref=tgt_adv_XSG10001&AFID=google_pla_df&LNM=14048570&CPNG=Home+Decor&kpid=14048570&LID=25pgs&ci_src=17588969&ci_sku=14048570&gclid=CIOF0Lmpqb4CFeZaMgodm00AMA http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=22024&cmpid=01csegpl&ref=6111&subref=AA&CAWELAID=823286718&CAGPSPN=pla&catargetid=530005150000091069&cadevice=c There is also the option of installing a retractable screen door inside the trailer, a pull dowm, pull up screen to cover the opening. http://www.thisoldhouse.com/toh/how-to/step/0,,20177937,00.html This link presents instructions for building your own wooden screen door, the original intent of the question. One other suggestion is for doorways which require screening but will not be used for entering or exiting. Build a window screen, no handle or hinges, the size of the door opening. Include a crossbeam to hold the shape of the screen. You can pop this into the opening or use velcro to allow the screen to sit securely over the opening and still be removeable. Personally have used this over many years for a doorway which gets opened to let air circulate but is not used as an entrance. Had it made years ago by a local hardware store to my measurements; still works great keeping pigeons, insects, and raccoons outside. There are now commercially available products of a similar nature. http://www.thisoldhouse.com/toh/how-to/intro/0,,1067855,00.html http://www.ebay.com/itm/Instant-Screen-Door-Standard-Frame-36-Black-Mesh-Screen-/271237843490 http://www.vouillemin.com/en/trade/import-export-products/fly-screens/door-fly-screen/ Included this link from the United Kingdom because the product is a unique example of door screening. http://www.bestpestcontrol.co.uk/aluminium-fly--insect-chain-door-screen---silver-432-p.asp