Cheap Teardrop.
Go to Louisanna at the end of the month. Visit Madjack and say happy birthday. Eat, look around and be merry.

Or go to Anastaisia and get ideas.
Buy cheap Lousianna boat trailer. (or other) $50
Buy cheap plywood (

)
Find glue at flea market (NOT)
Get used screws (NOT)
Make own window
Camp
Truth is you can do it, do you really want to. Look around for an inexpensive trailer or PM GPW about trailers .
Make it small. A big freebee will cost you more in materials. Then Make any shape you like. The weekender is easy but any shape using 4x8 sheets is good. (4' high and wide)
If you need light weight too you can make your framing members by splitting 2x6's. It is a lot cheaper than buying 1x2's. Watch for large knots or wavy grain patterns. Your cut offs will curve. (clamp pieces back together after cut to minimize warping.)
Buy good glue---Tight bond 3 is great.
Luan sides and roof = $40 Check each piece carefully.
or 1/2 sides and luan roof not much difference.
1/2 bottom=$16-$20
2' x 6' = 3-4 @ $4ea.
interior layer is choice.
glue = $28 gallon (you might not need that much, but I did)
screws = 2@ $6 (you may not need that many)
trailer = $50+
Primer = $ ?
Paint = get the good stuff (porch or Sears has a 30+ year house that will probably be good. Urathane based)
Gardners fiber coating (brushable)=$7
Hinges and windows
Brushes and squeegys
Bolts, washers and nuts, to bolt it down
Galley hinge = Aluminum piano hinge is cheap. A galley hatch isn't as hard as it looks. You can leave it closed up and cut it away later.
Trick is to put your money into good materials and cover with good finish. Try to not make waistful mistakes. Planning every step and reviewing just before you do it will help a lot.
Enjoy