I think the only things worth spending actual money on at this age are baby links (about £4 from ELC, I think, and actually useful for you as well as nice for the baby) and some stacking cups (I got ours from Sainsburys for about £5). If your budget runs to it, some squeezy plastic animals for the bath might be nice in a few months (would def buy these new as they tend to go a bit mouldy inside after a while no matter how carefully you clean them). I bought some for about a fiver and my DD is still playing with them at five so that is more than four years of continual use! She also still uses the baby links as bracelets and the stacking cups in the bath.
At about a year old, I used to sit my daughter in a large cardboard box with a load of torn up newspaper and let her throw it around and bury herself to her heart's content. She absolutely loved it. Other ideas for that age that are really nice and also cheap would be things like a bowl of water with soap/washing up liquid and a whisk (outside or on kitchen/bathroom floor), clear plastic bottle half filled with water/food colouring/glitter and a drop of something that will bubble, plastic bottles containing a couple of tablespoons of rice/beans/lentils/salt (they all make different noises), 'painting' on outside floors or walls with water and a big brush or chalk drawings outside, buy really cheap big bag of lentils or rice from eg Indian shop and put in a big washing up bowl and let her bury things and dig in it.
Later on, next year, when she's starting to walk, it's definitely worth getting a cheap toy pushchair or pram or maybe a trolley with bricks as that's another thing that will be played with for absolutely years. I think ELC do really cheap toy buggies. Toy plastic food will be a lot of fun later on, too, and a cheap plastic tea set.
A lot of these are for older children, but it might give you some ideas for later on. I think the improvised toys have always been my daughter's favourites.