Get quotes from different places for carpets.
If you buy a roll it’s usually good value. We carpeted, stairs, large landing, 4 bedrooms, lounge and dining room for about £1700 with underlay and fitting. One of the girls rooms was a different carpet. The carpet was probably lower mid range, we bought it as a cheap fix expecting to replace in a few years, (light carpets and small people) to be fair it’s been down 2 years and still looks lovely - the carpet cleaner is our friend lol.
It started off as, ‘could we get quotes for the two girls rooms and if the price is good we’d do the baby’s room’, they pointed out with the waste they could do the stairs, asked what the budget was and us guessing from what we paid in the last house, (all different carpets, varying quality, quite expensive from another carpet place) if it included stairs, we said about 1200, he said he could do the whole house for that! Well we were so happy as we’d lived with nasty carpets since we moved in thinking we couldn’t afford to replace. The company let us pay over a couple of months and they did the upstairs one month and downstairs the next.
We ended up going for a slightly better quality than he suggested and to be fair to the company they were absolutely spot on. They had a diagram of the roll showed us how all our rooms and stairs fit into the roll.
Shop around, ask about a roll and have a look at B&Q and H&M type places for readymade blinds.
The problem with a roll is you have the same colour throughout the house but we love it.
Ebay have some cheap vinyl, carpets, underlay and offcuts.
What are the floorboards like? Would take a bit of work but if they’re nice you could sand, varnish/paint and throw some rugs down. On Grand Designs polished concrete floors seems to be a thing...
If you’re paying 2 lots of rent for the first month could you and your OH book a couple of weeks off work to prep it whilst your still in the other house? Might have to do it but by bit but hopefully you’ll get your deposit back and the extra each month from the cheaper rent you could put into carpets etc.
There is a page on Facebook, DIY on a budget and there are some amazing projects on there.
Congratulations on your new home, it might take a bit of time and work but you will make it lovely.