You are tearing your eyes up (pulling the skin around them, etc.) if you are wearing eyeliner ALL THE TIME and, of course, washing it off. Your face needs a break, needs to breathe and relax. Also, the eyeliner look is so harsh for every day. It's hard to get off that cycle. Sometimes I think that I'll have a more natural day and end up getting all decked out because I can't wear one without another.
I love glamour, so I'm always working on my looks. (Let me add that I'm really good at it, too. People ask me often who does my make-up or where did I have it done. I am the designated make-up person for weddings and other special occasions.) Look closely at the models in magazines and on TV (when you have time), and try to emulate their looks. Don't try to look like them, but look at why certain looks work for them and figure out how to make them work for you. (Example: I read a few years ago that make-up artists for a certain star use lighter shadows between her eyes and her nose to make her eyes look further apart. Well, I sometimes want my eyes to look closer to each other, so I use darker shadow near that area, and it works for me!) Instead of eyeliner, you can use shadow in the same places--eyelids and below. You could, also, use one (natural) shadow color around your entire eye and then put on mascara.
Regarding how much to spend, determine what's most important to you. I don't mind spending money on mascara and lip gloss and moisturizer and foundation--my staples. They really do set the tone/scene for my look. Lipsticks (ugh!) and shadows and blushes and eyeliners can come cheaply. One trick to a more natural look is not to use foundation over your entire face. Put it on the spots that you want to conceal and blend around it. Look into what moisturizer is best for you; I absolutely love Dove face lotion and Nivea Natural Tone face and body creme. I alternate. Apply your moisturizer somewhat liberally. (Rub it in like lotion, but your face should look a little oily.) Then, give it about 5-10 minutes to soak in. Take a hot wash cloth and just steam your face by placing it over your face until it's not so hot anymore. Once you remove it, use your foundation like concealer and just apply it over any spot that you want to cover. Blend in the area around it, and apply powder to your whole face...to even it all out, but still allow for a little "glow". Don't go for a matte look unless that's what you're looking for. Use a little bronzer on your cheeks instead of the full color of a blush. The more natural and less dramatic your look, the easier it is to get away with wearing less glamour product. It'll make you look healthier, too, and feel lighter.
Hope this helps. It sounds silly, but it's hard to move through your day if you don't feel attractive.