you should buy a planer anyways. I have a thread going on constructing the dome clock. I purchased the lumber S3S- surfaced 3 sides with one edge left in the rough.
3/4" thick. im able to rip the lumber in half on the table saw and finish it to 1/4" with the planer and saving a LOT of money over purchasing all the lumber already 1/4" thick.
it is fun and enjoyable to make lumber from pallets and rough sawn lumber, but theres something important to consider:
a planer and jointer go hand in hand for the task. one face of the lumber needs to be flattened before planning. if it isn't flattened, a planer can plane any warp,cup, or wave into the wood. a jointer flattens one face, then the planer makes both surfaces parallel.
it is possible,however, to built sled of the planer to flatten lumber. there are quite a few videos/articles on the www showing how.
as for the pallet wood, something to consider is the moisture content. beings how I worked in a pallet shop, most pallets are constructed from quite green lumber.
however, pallets that are shipped from other countries have to be treated to kill any bugs that can be in the wood and that's done 2 different ways; either heat treating, which there should be a stamp on the pallet indicating its been heat treated.
or with chemicals.
what type of planer? welp, I suggest the highest quality you can afford. now, the dewalt 734/735 get the best reviews for benchtop planers. but there are others out there that work pretty good. I have a delta tp305 that's over 10 years old and has a LOT of use on it. the downfall is the knives- the edges don't last long on hardwoods.
cutech is a new company that has a line of planers. the model 40100H-CT is called a spiral cutter head, but its more of a segmented. instead of 13" blades, it has inserts. leaves a great finish and its pretty nice in the even that a nick occurs- which always does on planer knives, instead of having all knives have a nick and needing sharpening/replacing, the insert that is nicked can get rotated to a new cutting edge.
what I know of my delta and read of others, it seems that all but the dewalt benchtop planer snipe.
as for low end planers, that's hard to say what will happen purchasing something inexpensive. planers and inexpensive don't really go together. are there replacement parts and blades available?
imo, id suggest either cruising craigslist for a used dewalt or look into the cutech planers.
one other thing to consider:
other than the dewalt, quite a few tool company names can be on the exact same planer- looking at a model of the cutech and rikkon, one model is identical with quite a different price. a rigid and craftsman model look identical,too.