I live in London, and I play at a local gaming store with a dozen or two people playing Commander most days and varying people each time. I also play at a local commander group of a couple of dozen members that has biweekly meetups. I've never yet seen anyone play a card from the reserved list, either in my own games or glancing at other peoples' games. That isn't to say people never do, but it's not really a common thing that I've seen, let alone a necessary thing.
Many people play with the precons -- those are about £30 retail in London, or $50-60 in Australia when I was living there. Maybe they've modified them a bit to do something they like better.
The last deck I built (
this Mathas one) is valued at $150, specifically just because I had some more expensive cards available. I then swapped some cards out for equivalents to reduce it to $85 for others wanting to build a cheaper version. Some of the most expensive cards were there just because I had them: I had a
Blood Crypt instead of a
Bloodfell Caves, and a
Ravos, Soultender instead of a
Palace Siege,
Needle Spires instead of an
Ancient Amphitheater. I don't consider the substitutions to modify its power level that much: Ravos is easier to get back, but Palace Siege is harder to remove in the first place, etc. If I owned absolutely none of its cards I think I'd tune it to something worth about $100 before buying it, give or take $10, because I just wouldn't include the shocklands or manlands and that immediately chops off $20+.
When I build Commander decks I specifically avoid needing more than one or two cards in the deck that are worth more than $5, unless I happen to already have them. I've been playing since ~2013 so I only have a handful of those, and not these crazily expensive old cards. I have bought a
very small number of cards worth approximately $10 for deckbuilding (like
Contagion Engine for a -1/-1 counters deck). I have bought, I think, three cards total that were $20-40 -- one of those was
Animar, Soul of the Elements -- and I changed my mind about using the other two and plan on selling them. The only other expensive-ish card I have any plans to buy is
Monastery Mentor, the price of which has finally fallen to around £10.
Some people have fairly powerful decks. They don't need to spend a lot to do it --
Zurgo, Helmsmasher or
Scion of the Ur-Dragon or
Sheoldred, Whispering One can get pretty bonkers in a deck valued only ~$100. One of the most brokenly powerful cards in a Zurgo deck is
Worldslayer and that costs
fifty cents.The commander players at the places I mentioned are conscious that decks have power levels (we say the precons are mostly something like a 2-2.5 out of 5, and then from there manage to gauge how much more or less likely our deck is to win than any precon). If there's a lot of people we can consciously self-arrange to play with decks of a similar power level, and I personally have the most fun playing around that precon strength level. People with a significantly more powerful deck at the table quickly turn a 4-person free-for-all into a 3v1 match with the target on themselves. If I'm playing against someone with a far too powerful deck for me, then after I lose I thank them for the game, shake their hand, and get up to find a table more suitable for my decks' power level and/or find a new table.
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Basically what I'm getting at here is I've never seen or experienced a real price barrier here in Commander, nor is the Reserved List a barrier or even relevant (because its cards aren't important). If someone does spend crazy amounts to make their deck crazily powerful powerful, that's not necessarily
better for them -- they won't have many people willing to play with them a second time, except perhaps people with similarly powerful decks. If someone played a
Volcanic Island against me, I wouldn't bat an eye any more than if they'd played a
Sulfur Falls or a
Swiftwater Cliffs. There are no Reserved cards I have ever needed. If a deck needs crazily expensive cards to function and there are genuinely no alternatives, I don't build that deck and instead refocus on the thousands of reasonably affordable cards.
Price and power isn't even a real issue on the reserved list.
Donate (reserved) is cheaper than
Tarmogoyf (not reserved). And I've never seen anyone play Tarmogoyf in Commander either and don't expect to. There
are some crazily powerful cards on the reserved list, but e.g. the Mox Anything cards are banned in Commander.
If Angus Mackenzie became $500+ I wouldn't care. I don't need him to play. If anyone else has him and uses him as their commander, great, that'll be fun to see -- but I'm not really worried about him being required. He's not something crazily powerful. He dies to a
Terminate like any other creature.
If you think you need to buy Reserved cards or expensive cards... well, you don't. If you think everyone else is doing so, they probably aren't. If you think your deck has to be crazily powerful, it really doesn't.