Don't spend a penny until you have seen the group you like, seriously. If you don't know what to have and cough up on say 1280s kit and join a WOTR group you will have wasted much of your cash.
The looking aorund for a group can be hard but also enjoyable as you get to suck them and see. And unless you are hooked to a particular era, say within a 50 years then go for the group that you like first and foremost, the group is much more important as they will be your family, sad I know but they do come in handy for a cup of sugar now and again, or a tent, table and chair.
whistles... pourpoints are doublets sleeveless or not...whistles....(see what you have let yourself in for WW
Hose can be made using a pair of reasonably close fitting trousers, certainly to get the lines by pinning the back the excess at the back to create a seam (ignore side seams), it also gives you the crotch height for the fabric. Cut along new back seam and lay out and use as a pattern. It does mean the loss of a pair of kecks but an old pair would do. First timers suggest doing it with a friend. I use this method to make open hose (I find them comfortable and am genetically unable to make closed hose.
With open hose you can easily go up to 1470s although you would not be anyone that important and you would almost certainly need to have your rear covered (assuming male) with somethign resembling proper underwear and a long enough shirt. Height of hose varies they get higher as the 1400s progress, reaching 'magic' hose height in the early 16th, ideally they should not be self-supporting until post 1500 or so.
Linen is more readily available than it used to be and worth the small extra price and it means you only have to buy it once, also if you join a group ask what bulk purchasing they might do to keep cost down, they may be able to supply materials at a better rate.
Accessories can be a real pitfall too, I would counsel the same circumspection as with clothes, accessories are more hit and miss than clothing sometimes. Certain things are more worried about by groups than others, eg teak salad bowls rather than reasonably priced turned treen ware that looks ace and is useable across a wide area, some groups wouldn't know or care about it.
Conversely getting a hand made bronze kettle made originally on 2nd Feb. 1465 and not having any clothig is also no good either
But it is as hys Grace rightly says down to the standards of the group you join, I would challenge the authenti nazi bit as I am sure a medieval shirt would not pass muster on say a 1810 rifleman. It is all about what you want and what the group wants. (Medieval - wide remit is full of grey areas, the later you go the harder it is to get away with stuff).
But have a lot of fun meeting up with people, the best bit, spend when you need to and when someone you trust has advised you.
Best of luck.