First thing to do is make a plan. What's your number one need? For us on the Gulf Coast, it was preparation for a hurricane. First, a BOB since we face mandatory evacuations. We also live very close to multiple oil refineries and thought a BOB would be useful. Next, for us, up to date car kit--fix a flat, jumper cables, water, food, etc. Home protection-- a .22 and a 12 gauge with ammo. Then, preparations for buggin' in for a category 2 hurricane--stored water, food, fuel, etc. Extra gas, a two week supply of pantry items, first aid, then long term food storage. We camp so we had a lot of stuff already so it was a matter of pulling stuff together. Among our first purchases--2 seven gallon aquatainers, 2 5 gallon gas containers, backpack for hubby, 20 pounds of rice, 10 pounds of beans, 2 extra of all the canned good we regularly use. We already had a way to purify water (we want to add a Berkey), multiple ways to start a fire, multiple ways to cook (we want a Coleman dual fuel stove and lantern yet). Oh yes, and the guns were early purchases too. We had been looking at them for home safety anyway and this was a way to get him on board.
We set a budget for preps and add weekly. We always buy canned meat at Walgreens when it's 1.99 (ham, roast beef, and spam), and our grocery budget includes 10% for preps. We got a membership to Sam's Club and use it for some things (we do buy a lot of all natural and/or organic but for preps we aren't as picky although we try for healthy high quality items as much as possible).
I've also started to cook more using our preps. We mostly eat meat and salad, meat and vegies (stir fry), or pasta. I've started cooking beans every two weeks (gradual process, hubby isn't in love in beans, yet), and trying to incorporate canned meat instead of fresh. Eating less meat in general.
We also revamped our lifestyle, which also made more money available for preps. We have basic cable, eat out less, and yes, we are making a HUGE effort to pay down our credit cards. We've also decided that I should go back to nursing school and I'm starting the prereq's in the winter.
Make a plan. Decide what you are prepping for and buy accordingly. We've been at it a few months and we have our kits, extra water and gas, and about a 3 month supply of stored food. Above all, don't get discouraged. It really adds up quickly as long as you are committed to doing something each week. It doesn't take a lot of money, it does take commitment.
Jackie