@m2193: I've had quite a bit of tea from David and Kathy at EoT over the years. I feel as though they have a reputation for being expensive, which I think is unfair, because to my mind at least, the price reflects the quality.
My rough summary just from memory of the ones that I've had, in case it is of any assistance:
2018 Zhang Hui Chun - Strong Roast Shui Xian (8g) - I've only tried it once, but I would describe it as 'chocolate roast'; very dark, very smooth, great if you want to practice the strong Chaozhou style of brewing or just try something that's been heavily roasted in a good way.
2019 Rui Quan ~ Jin Suo Shi Wuyi Yancha (15g) - medium-light roast, but enough oxidation that it comes across well (I don't like low-roasted yancha, but I've enjoyed a big bag of this over a year); quite elegant, easy to brew.
1997 "Horse Head Cliff" Shui Xian Wuyi Yancha (15g) - pleasantly aged, but still retains a bit of its youth, and the sui xian character comes across quite strongly; pleasant, relaxing tea.
2017 Handmade Tie Luo Han (10g) - medium-heavy roast (ie, neither too light, nor approaching chocolate; this is generally my preferred style), deep flavours, potent feeling, and I'd guess that it would age well. This is one that I've really enjoyed.
2018 EoT House Rou Gui Wuyi Yancha (25g) - pleasant everyday yancha; I've been brewing it very strongly in my imitation of the Chaozhou style, and it's done well. Medium roast, more particular about how it's brewed than the other ones here.
2019 Hui Chun ~ Bei Dou Wuyi Yancha (10g) - good example of a heavily-roasted tea (not yet 'chocolate' like the shui xian above, but a bit heavier than the tie luo han); compared to the 'full roast traditional' range from Daxue Jiadao, I feel that the Zhang Hui Chun ones from EoT provide much more feeling for me, but less precisely delineated flavours or aromas.
2018 EoT House Lao Cong Shui Xian (25g)- haven't had this one in a while, but I recall it being similar in roast style to the equivalent rou gui; perhaps a bit lighter in profile overall, and again somewhat more particular about how it is brewed than the others here.
Perhaps you could try the Zhang Hui Chun bei dou, the 2017 tie luo han, and the Rui Quan jin suo shi, for a comparison of different processing styles, but that's just me. And if you can, I'd recommend trying teh 1997 shui xian for an example of how aged yancha can taste, even if you only get a single session's worth to try.
I haven't worked out how those teas fit within your budget, but my own preference generally would be to try just a few in larger quantities (instead of trying all of them in smaller quantities), so that you can brew the same tea a few different times, without worrying that you've only got enough for a single session.
Something that I enjoy about the teas that David and Kathy source is that they tend to match my preference for teas that give me more than just flavour and aroma, and have a potent 'feeling' to them. But others will obviously have different preferences, and may simply not place any weight on the 'qi' aspects of tea.
Andrew