The Cottagers didn't use chemicals! So I'm assuming you are not going to use fertilisers, the cost will be greater than the savings you are going to make growing your own anyway.
If you are planning to turn a lawn into a planting area for vegetables, you will need to remove the turf. The easiest way is to cover the area with black plastic until the grass rots.
A quick way is to remove the turf with a spade, mark out squares about two inches deep with a sharp spade. Then, scoop the turf off, turn it over and store in a heap in a corner of your garden to turn into loam to be added back to your garden.
Digging the ground
Dig the area over removing as many large stones and weeds as you can, don't try to remove every stone it is impossible.
Providing the soil breaks up into reasonably small chunks there is no need to rake it over. Weeds that haven't gone to seed can be added to your compost heap. Weeds that have gone to seed like Bindweed and ivy can be rotted down in a plastic bag and then added to the compost heap.
Sandy soil is easier to dig. However, won't have as many of the essential nutrients clay soil does so you will need to dig in plenty of compost making compost
Chalky soils are dry, stony and low in nutrient, but by choosing plants that grow in chalky soil you can still grow a good selection.
How to test your type of garden soil
you may prefer the no dig gardening method explained here Gardening without digging
Preparing seed beds the areas you are going to sow rows of seed will need to be raked fine before sowing. Most seeds are sown direct into the garden. However, sow a few in trays, the seedlings can be sold at car boots, more than covering the cost of buying the packets of seed in the first place. Guide to sowing seeds.
These vegetables are easy to sow and grow with just basic care.
Don't fancy growing from seed. The best way if you can, is to buy organic seeds and grow your own plants from seed. However, if you are sourcing your plants from a garden centre. Be aware that;
Eight things that will help make your vegetable garden project a success.
Some of my other pages that might help.
Daily Telegraph research found that a
basket of six fruit and five vegetables from Tesco and Sainsbury's costs £37.20, compared to just £21.01 on average from four different independent greengrocers around the
country. Why pay £16 more for a basket of six fruit and five vegetables, plus the cost of driving to the supermarket. Keep it simple and shop locally.
We throw our hands in the air every time our local Butchers, Bakers, Greengrocers and Post office gives up the battle with the supermarket, but don't support them when they are open, preferring to buy and eat fruit and veg that has gone around the world twice, instead of buying local produce that is on average, £16 cheaper for a basket of six fruit and five vegetables.We let supermarkets get away with charging far more for fruit and veg than they should.