Those are "chip" or SMD resistors and carry very little current. They come in varying sizes and, in that application carry very little current (assuming all is wired up properly). An 1/8 W is more than enough, and there is no harm in using a higher-rated resistor (1/4 W, for example) if you're using one with leads.
Soldering SMD resistors is not terribly difficult, but you'll need to carefully measure the size to get it to fit the pads on the board. They're fractions of a cent each through a major component supplier like Mouser or Digikey in the US; it's the $7 or so base shipping that will be the cost. If you do decide to try to solder SMD components, a good set of tweezers, like the utility-grade EROP7SA (US$4.20) and a hands-free magnifier are highly recommended. I use the Donegan DA-5 OptiVisor (~US$40) as a reasonable compromise between magnification and enough room between my nose and the soldering iron or hot-air rework gun (8" / 20 cm focal length).