Ah, designer vinyl. Companies like Kidrobot have popularized it, but these days, you can find cool, pricey, not-for-play-or-action figures even in places like Urban Outfitters. You can collect Kidrobot's Dunnys (stylized bunnies, all with the same shape but each with a surface by a different designer, usually retailing for under $10), or focus on pieces by a particular artist.
Or you can go to ReadyMech, a project of the FWIS design collective, and print some free paper models to cut and assemble, with minimal equipment. (However, for best results, you need to use more equipment than the website suggests -- more on that later). The styles are as cool as anything available in the world of limited edition art figures, but as with most DIY projects, you save money by building them yourself.
Aside from the double-sided tape and thick matte paper recommended by the designers, you might consider a craft knife (X-Acto, etc), a metal straight edge, and a bone folder, for clean cuts and crisp folds. Printing onto light card stock might be helpful: if you can only print on thin paper, you might consider gluing it to light card stock with spray adhesive after you've finished printing, because the result would be more durable. A glue stick or glue pen might not be amiss. They say that each project should take you around fifteen minutes to complete.
Click on through for tips, tricks, and what I learned from building a ReadyMech of my own!
I finished my model in around the suggested time, and didn't bother to use a straight edge to cut with, just a craft knife. The only parts that gave me any trouble were the curves on the arms and hands, which not all of the models have; it seems like it might be easier to use a combination of a craft knife for the straight lines and small, sharp scissors for the curves.
My version is printed on regular printer paper. If you printed on card stock, you'd almost certainly need to use a straight edge with your craft knife; card stock takes more pressure to cut, and you really don't want to slip and cut your hand while you're doing it.
I did use a bone folder to score the folds before I folded them. I got it "more or less" on the lines (the bone folder probably really does need a straight edge!); nevertheless, the result was fine.
I also used a glue pen rather than double-stick tape. Deciding which tabs to glue down first was the only other small difficulty, but with careful handling, tab order doesn't matter much.
Another tip for working with paper models: have a set of markers nearby, and carefully color just the edges of the paper after you cut your shapes out. This will remove any white edges that might be showing on your model, and your model will look more cohesive. The thicker the paper stock you print onto, the more you'll probably need to do this! I didn't take my own advice this time around (look at the front edges of the arms), but if I had printed onto card stock, coloring the edges wouldn't really have been optional.