Hi Talia. Perhaps aim to bring a smaller area in to use initially and then build each season from there. This helps to keep things manageable and you can adjust more easily to the required task.
Do check out local farmers for huge amounts of low cost horse and cow manure, if you have access to any of course. As an example, I got 110 wheel barrow loads for £40 of well rotted cow manure; a good bit cheaper than the local garden centre! Hope that helps.