A 2-oz bar of polymer clay (whether it's FimoSoft or another brand of polymer clay) is about 1.75" x 2.25" x 5/8" thick --I just measured a bar of the Premo brand but a 2 oz bar of FimoClassic or FimoSoft, Kato Polyclay, Scupey III, or Cernit would be the same volume of clay but a slightly different shape.
(A "brick" is usually thought of as the larger size that polymer clays sometimes come in --12 to16 oz)

You could make probably 5-10 "charms" like those, depending on their size from that much clay, but of course they would be all one color unless you just wanted to paint over the polymer clay to change its color (use 2 coats of acrylic paint if you do that, and wipe with alcohol first to degrease).

You can also just buy a bar or two of white polymer clay though, then give it color by mixing artists' oil paints into it --you can get little kits of oil paint with 8 or more colors-- or by mixing in alcohol inks like Pinata or Adirondack (... I wouldn't suggest the boxed white "Sculpey" polymer clay unless all your shapes would be rounded because it's the very weakest of the polymer clays after baking anywhere it's thin or projecting -- so white Premo, Fimo. Kato, or Cernit would be best.)

Also, all the colors of polymer clay can be mixed together to create almost any new color so you can just buy a minimum of 5 particular colors then be able to mix most any other color... those colors would be a very pure red, blue, and yellow, plus black and white to darken or lighten the mixes... and actually magenta, turquoise and lemon yellow work even better than red, blue and yellow.
So you can either mix those colors of clay together, or you can mix the oil paints or alcohol inks to any color you want, then mix that color into the white clay.
If you want a lot of information on mixing whole palettes of colors using polymer clay, and/or recipes for creating specific colors, check out this page at my site:
http://glassattic.com/polymer/color.htm

Some of those charms also used a clear gloss finish on top too (not necessary to use on polymer clay, but will give gloss when desired). When using polymer clay, you can't use finishes containing petroleum-based solvents though because they will eventually eat into the clay, but you can use a clear water-based gloss polyurethane (from the hardware store), or the "floor polish" called Future or Pledge/Future, or clear acrylic fingernail polishes, or even gloss acrylic mediums or thinned permanent white glues, and other things. There are two gloss finishes made specifically for polymer clay but they're much more expensive and the Sculpey one is kind of thick so not the best.
If you want more info on finishes to use on polymer clay, check out this page:
http://glassattic.com/polymer/finishes.htm

And lastly, if you want a bunch of LESSONS on making miniature foods from polymer clay, and other examples of them, check out these two pages at my polymer clay "encyclopedia" website:
http://glassattic.com/polymer/miniatures.htm
...and you might want to check out the "Table of Contents" page too to check out all the other stuff about using polymer clay that's covered at the site:
http://glassattic.com/polymer/contents.htm

HTH,

Diane B.