i've been reading, and i've found that most step guides have the guy start with the right foot, i've always thought it was left foot?

Ok. I've been dancing international since - hm - two years.

In (vienesse)Walz, of course, you're starting with right. It's the opposite of the american style.
In Rumba or Chacha, you make to begin something, which called an 'appell' (i don't know this word in English) with the right foot.
It's like saying to the woman 'I want to start'. And then, your moving with the left foot foreward.
In Samba and Quikstep it's the right foot again. Why? I don't know.
The only dance, in which you begin with the left foot, is the Tango and the Jive (Boogie Woogie and Rock 'n Roll included)

I hope, this was the answer, you'd like to get

There is no definite answer to this. It depends which figure the guy wants to start with.
Natural (right turn) figures start with the right fooot and reverse (left turn) figures start with the left. It's most common to start a tango with a walk on the left foot.
Cha cha and rumba basics start with the left foot, samba could be either, jive is usually left foot and paso generally has a right foot Appel.

Many teachers think it is easier for beginners if every dance starts with the left foot, so they add an extra step if necessary, such as a walk before a slow foxtrot feather step. Personally I think it just complicates matters when beginners progress to more complicated routines.

I generally start with a reverse figure, and hence my left foot, because that way I am facing into the room and can see where the other dancers are. I hate it when somebody walks onto the floor, turns their back on me and all the other dancers, and counts the music for a few bars while waiting to start with a natural turn.

The best answer I could give is not to start with either foot, but with your body. If you move you body weight onto the foot you will not be moving, and your partner moves with you, then there is no way that she can go wrong.

"Many teachers think it is easier for beginners if every dance starts with the left foot, so they add an extra step if necessary, such as a walk before a slow foxtrot feather step. Personally I think it just complicates matters when beginners progress to more complicated routines."

That's not really the reason. In the international standard, a lot of the figures won't work right unless they begin with substantial body speed as a result of a preceding downswing. The preperation step on the left foot is just that - an abbreviated downswing lowering so the right foot step can be taken with pre-existing body speed. Reverse (left turning) figures can tolerate the lack of preperation better, so we may not take an actual prep step on the right foot before a figure that starts with the left.

I am well aware of the concept and use of prep steps, and anonymous3 makes a good point that they should form part of he previous bar of music. However that is too complex for a beginner dancer and it has only a limited use on the social dance floor.
Most teachers that I have seen teach beginners that the feather step begins with the left foot walk and count it on beat 1. They also tend to add the following left foot slow which strikes a chord with the beginner who can now relate a five step feather to Victor Sylvestor's slow foxtrot count of SSQQS. Later, when they are asked to dance a feather following another figure they are totally confused and complain that they are "on the wrong foot".

I also see the preparation step expanded because it has become the start of the dance and now looks rather flat. So, let's add another step so that we can swing into the prep step. etc etc etc.

The classic example is a four bar introduction to a Viennese waltz. This is fine in a competition where everyone starts together doing a similar thing, but it causes total chaos if used on a social floor when the dance may already be in full swing, but "that's how we were taught to start!" they say.

Achilles, At the very start of a W F or Quickstep. There is a Walk on the left foot by the man which by most is a heel lead. It is called a preperation step and will be on the 3rd beat of the bar of music in Waltz. In Foxtrot there is a preperation step again on the mans LF. Try to do this one on the beats 3 4 which allows you to start your Feather Step on the count of 1 2. Same with Quickstep ,walk in and make sure you are on beats 3 4 on your preperation step.. Then you can start your Quickstep on 1 2 . If you are just a Social Dancer it is of less importance. But in the F Q it is better to dance 1234 rather than 3412 In a competition it is very important to be in rhythm with the music in fact you have no choice.
Latin Rumba and Cha. You can start with the RF to the side without weight and roll onto it on beat one. But if you watch most of the top dancers Donnie Burns being one. On his tape he positions himself with the RF behind the LF and on the toe. With him the first step on beat one becomes a forward walk. In the Cha the same. It is very effective in the Cha if you wish to start with a Lock ( correct name Latin Cross ) just dance 4 & 1 starting, again with the RF Having said that in our studio in both dances we stand with our LF behind RF Let beat one, the first beat go by, and begin dancing with LF on the beat of two. It sounds a bit complicated but it isn't. Just choose which you prefer, they are all correct.

There is no 'right' foot to start out in VW; it depends on the figure you use. For insteance if you gegin with a reverse turn, you'd use your left foot.

Doesn't matter a bit. Just make sure her weight isn't on the foot you want her to move