
Hiya VonJud! Welcome to the world of hobby-addiction.
Before I address your questions specifically, it is worth mentioning that many different rule sets are used by the folks around here. Even many of those who play with the GHQ "Microarmor, The Game" rules often play other rules too.
Some rule sets have very specific recommendations for basing your models. But most experienced microarmor hobbyists have developed their own preferences, which may or may not co-incide with any particular ruleset.
I have played more than half a dozen different rulesets, including two that were published by GHQ in years past. But I have never played with the "Microarmor, The Game" rules, and so can not advise you on the particular suggestions/requirements of that set.
I have never based my vehicles. I am not a big fan of the visual effect of bases with miniatures. I want to see less base, not more. So I only mount items which are really awkward to use in the game without bases ... vehicles pulling trailors, or horse-and-wagon sets get put onto bases, but not regular tanks, APCs or trucks.
Over the years I have tried many materials for basing my infantry. I started using styrene plastic sheeting cut into small squares. For a while I used card stock (regular cardboard, a little thin, bought in large sheets at my local crafts store). I tried metal bases from the hobby shop, and washers/slugs from the hardware store.
Finally I have settled on pennies. They are very robust, and so provide reasonable protection of my investment (of time) in the bases. So this (and the many wonderful pics on this board) have encouraged me to do a better job on my bases, and they really do look a whole lot better than they used to.
I find pennies are always available ... I used to get VERY frustrated when I was just one or two bases short of a full unit ... something that I always seemed to discover at night, after everything was painted and ready to go ... everything except for the last two stands I needed for my game in the morning!

But I can always find a few pennies around the house (just look between the couch cushions!). And it is hard to beat the price. I've found places that will give me almost 100 pennies for a dollar! No, really! Can't beat THAT price with any other basing material.
Here are a few examples:

My French infantry squads are based on cut card stock. This pic is from a game I held last year. This was the last card stock force I built, back in the early to mid-1990s. Originally the card stock was just painted. Later (after seeing all the work in this forum) I flocked them. But the card stock doesn't really hold up well enough for the "full treatment". So paint, and some flock, and that's it.
BTW the French 25mm AT gun in the picture was done just a couple years ago, and is based on a penny.

This is a pic from Thunder's website (
www.microarmor.com) of a game we played at a con a few years back. This Soviet infantry (figures by a UK vendor) was the first I based on pennies. I used white glue to mount the figures, and tried to put enough on to obscure the figures' own stands a bit. When dry I painted it. Net effect was pretty primitive.

Here in a later game the same forces have been upgraded with a touch-up on the painting, and a bit of flocking on the bases. Still fairly basic, but clearly looking better.

Romanian squad on a penny. This is my most recent army. I have used several techniques learned on this forum, including flocking with both "grass" and "shrubbery", placing some sand to give the appearance of stones, and the use of acrylic matte gel (colored to match dirt) to give enough depth so that the figure's own bases are not visible. The matte gel works as an adhesive for the flocking, but is much easier to work with than white glue. I'm very pleased with the way these guys came out.
Hope that helps.