Some people buy one but tbh
a) how many times are you going to use it
b) you will get to hear the heartbeat at appointments
c) what if you can't find the heartbeat (I assume your not medically trained and sometimes midwives take a while when baby is in the wrong position) - it could just make you worry more.
For other stuff there are 3 main areas you need to cover
Transporting baby - so pushchair, car seat, sling if you want one.
Pushchairs best to buy second hand as they cost a fortune new and you can pick them up in almost new condition for often less than 50% of original price. Gumtree/ebay/NCT sales are good places to find them.
Car seats best from new so you know that a) they will fit your car and that b) they haven't been in an accident.
Slings - ask for advice online
Clothing Baby
vests and babygros (around 7 of each to start with and get more if needed)
A couple of pairs of socks
Sleeping
Cot + mattress + bedding. Bedding needs to be basic. Sheets, and the either blankets or gro bags. No to cot bumpers, duvet/pillow sets. Make sure mattress has machine washable waterproof cover and see if you can get spare (or ikea sell flat waterproof sheets for cots for £4.99). If you buy cot second hand make sure you buy mattress new. I found it cheaper to buy new cot from ikea for £39 (mattress was around £20) as with 2nd hand ones I then had to get mattress made to measure which pushed up cost considerably.
Moses basket can be useful but they aren't in it for very long so get one second hand. Best to get stand with it otherwise you are bending to floor level to pick up baby.
Other
Nappies
Bottles and steriliser if not bf
Muslin cloths
Cotton wool balls (can't use baby wipes for first few weeks)
Baby monitor (though worth waiting to see if you need one)
I like a bouncy chair as found it useful when dc1 was tiny to stop him crying when eating etc. And there may be other things you find more useful but worth waiting and see what you feel you need.