Since you mention using FPGAs for algorithmic trading I can only guess that you wish to employ FPGAs as some sort of signal processor. I would suggest investing in an FPGA driven Software Defined Radio (SDR) You'll get the best of many worlds as an SDR does something that is immediately useful, and demonstrates how the FPGA fits into the larger picture as a part of a signal processing chain. Once you understand the complete signal flow from beginning to end mastered, building the signal processor you have in mind will be far easier. You will need to brace yourself to learning at least 6 different languages, including VHDL, Verilog, C, Python, Javascript, and Go.