If you want a board with good English documentation, you are most likely going to overpay for it because FPGA dev boards are a very niche product targeted at professionals that can afford it (or their companies can afford it). Many companies like Terasic offer decent educational discounts if you are a student, which can help. If you don't mind fucking around trying to get shit to work, however, there are much better bang-for-the-buck Chinese FPGA dev boards on ebay and AliExpress, but expect zero English documentation or support and having to figure everything out yourself. It's doable for the experienced, but probably not what you want to be bothering with as a beginner, nor what you want to be wasting time on as a professional. In other words, a classic product for people whose time is worth nothing :^)