I would say do not buy new appliances. If cupboards are really tatty then replace, if not, just replace the handles - works a treat for freshening up your room.
Repaint walls, change blinds if you can do that cheaply. throw out anything old and dated (or put into storage), and buy new accessories (soap dispenser, plate rack, washing up bowl) organise cupboards as buyers might want to check space situation in kitchen.
Do floor if you can do it cheaply, and if it needs doing.
Make sure the kitchen is spotless - clean the tiles/grouting, the door and woodwork,
For the rest of our house - we repainted the hallway, cheap and light (it was dark, we have not got around to doing it how we want it!), threw out some old tatty furniture, made sure the new duvet set bought for our wedding is on the bed whenever we had viewings, cleaned the carpets, polished the floors, cleaned windows inside and out, put the brightest lights in the wall lights, filled in holes in walls (nail holes etc) and repainted over, took down some of our personal photos (not all, but some as we had lots), and some of our paintings/artwork to minise/allow people to visualise there own stuff). Cleaned all the woodwork. It looks like a new flat!
Also - for me, a bit put off when I look at houses is that 'just cleaned' smell. It always made me wonder what it might be masking. So, I always clean thoroughly every night when I had viewings, and put on some nice oil smells, then did the tidying the day people came round, then the fresh smell would be a vague 'this is how is always is' smell. Do not use raw bleach. It stinks.
Unfortunately, with all this stuff going on, we still did not sell. So, now, we are continuing this upgrading without spending a fortune, replacing light fittings, door handles, the little metal bits on the floor by doors that hold the carpets down, light switches.