You've been warned. BrickLink
You can seriously spend hours "window shopping"........or actually shopping for Lego windows (there's a category for that). You can find old sets, exclusive sets, pieces, minifigs, etc. A few years back, I did a break down of the parts I wanted and how much it would have cost if I had bought the cheapest set a particular piece I wanted from that set. I think I ended up spending around $15 dollars for the pieces and to get them from buying sets at their cheapest was over $300. Now I didn't get all the wonderful pieces that come with the sets, but having only $15 to spend instead of $300, I think I came out feeling pretty good. My first ever purchase on there was for the windscreen (canopy/cockpit glass) that came with the first Star Wars sets. I think I bought 8 of them for under $1 a piece. That cheapest set that part came in was $30, so you can see how I made out on that one. I didn't have 8 x-wings to show for it, but I did have the parts I needed to finish off 8 space ships I had made. Some custom items have been appearing on BL also which is where I ended up getting some awesome minifig capes.
Fleshie minifigs are the result of licensed sets (LOTR, Star Wars, Super Heroes, etc). A lot of the younger generation have been warming up to them because they look "normal" and are have been readily available for the past 5-10 years. People like me who have been into the hobby longer aren't ready to commit to the "fleshie" trend. I grew up with the yellow heads and I have 100's of minifigs that way. I will admit that if I had to choose between the pre-2000 yellow minifigs and the fleshie minifigs, I'd go "fleshie".
Don't feel pressured to paint, cut, sculpt, decal, or dye your way into customizing. Customizers like BrickForge try to give people the incentive to use something outside the box without having a ton of skill. Not everyone can sculpt some space armor or cut an existing sword to make it look like one from LOTR ( I know I can't). Start off little. Make some decals using an ink jet and finding a design off a public site like Brick Shelf.