Please start by asking friends if they have any baby things they don't need any more. Loads of us are perfectly happy just to see things used, or pass on the favour of things being given to us when we needed them.
When we had DD we concentrated on
*somewhere to sleep:
Options are:
Cheapest - co-sleep with you, if safe (google safe co-sleeping for up to date advice)
Middle - travel cot. Can be bought new (on sale) or second hand for around £20. Disadvantage is you have to reach down low to get baby out and mattress very thin.
Middleish - cot. Lots on eBay at £50ish and friends with toddlers will be keen to get rid of theirs (maybe for free). You need a mattress too. Cheapest new option is from IKEA. Cot for £35 and mattress is £15.
Expensive - Moses basket for first few months and then cot as well.
For everything bar co-sleeping you will need sheets - a normal single sheet cut up and hemmed will make 4 sheets which should be plenty.
Blankets a couple of small flat sheets (again you can make these) and 2 cellular blankets is all you need. A MW will teach you how to swaddle with them after the birth. A more expensive option is gro-bags, practical but not essential - your baby will be too young to use them straight away anyway.
*Something for the baby to be carted around in.
If you have a car you'll need a Car Seat. 2nd hand is fine as long as you know the person giving/selling to you and that it's not been in an accident.
Then either a sling or a pushchair. Their are separate topics for them on MN and the posters there will be able to point you towards your cheapest suitable from birth options.
With pushchairs I'd start by looking at lie-flat umbrella folds. Car boot sales are brilliant for prams. Especially because they're on grass so you can tell what they're like to push!
I understand you can make a sling with jersey fabric as well?
*Something for baby to eat:
Breast feeding is obviously free, stick with it if you can. You will need nursing bras, or bras that are soft structured enough you can pop a boob out comfortably.
Breastpads - get a couple of packs of washable ones from boots and start chucking them through your washing machine a few times before birth to improve their absorbancy.
If you'll be using formula try the cheapest brand first because you can't get any discounts/offers on it. The own brand bottles and teats will be fine.
*something for baby to wear, concentrate on babygros and vests so you can double up if it's cold. Ask knitting rellies for cardigans, hats, booties - check charity shops and boot sales for these too.
*for you/birth:
Maternity pads. 4/5 packs, can probably switch to basics sanitary towels after that.
Clothes - use a hair bobble twisted around the button hole at the top of your trousersand looped around the button to make them last longer, then elasticated waists. If you aren't too worried about looks, try big sizes of men's clothes in primark or wherever.
*Baby care:
Don't buy sudocrem they'll be a free pot in your bounty pack after the birth.
You don't need any other toiletries to wash a baby, just warm water and a flannel.
A sculpted baby support that can go in your bath is really handy, but you can also hold them and wash them in a sink (ask the MW to show you how) or get in the bath with them.
Nappies, reusable are cheapest long term if you can buy second hand in bundles. As far as disposables go the most basic brands are absolutely fine. Aldi's are highly recommended iirc. Take a calculator with you to the supermarket so you can compare prices.
For wipes, you cheapest option is flannels and warm water. They can be washed like reusable nappies in the machine. Otherwise look out for bulk buying discounts.
Muslins - basically handy for catching sick. Go to a fabric shop, buy a meter, cut and trim yourself. Could look for them 2nd hand also.
hope that cuts your list down a bit.