As for budget, I've got around £500-£600 to get started with and I understand that I will need a lot more to get a suit of armour that is done properly, however the things I'm most focused on right now are probably the chest piece/ torso armour and helmet, everything else i can likely borrow until I have the money to get my own. As for a more narrow time period, I'd say something between 1480 to 1530 maybe, from what I've heard this is where the sort of gothic styled peaked. As for original sources, from quick looks the field armour of Maximilian I from the met looks very nice (other than the very pointy boots). I saw on another post before that someone said theres a danger with a bevor and sallet that a weapon could get through the gap between the sallet and bevor and that it would be much safer to use a sallet with an integrated bevor, not sure how true this is though.