DIY large print - I did this for a temple picture only mine was slightly smaller than 3'x4' so Staples only charged me $3.49. Baseboard and a miter box for the frame, spray adhesive to attach picture to hardboard (which I'd recommend over a foam board) and Mod Podge rolled over to texture and protect. Super inexpensive and it looks great over my kitchen table!
$10 antique flea market widow pane and a $4 black and white engineer print from staples... Staple gun the print to the back of the window and hang wires, easy living room wall art. Easiest Pinterest project I've ever done!