Are powers such as roy harper and tera counted as payment powers?

any power with a Arrow after it is a payment power.

The system is "Cost for payment power --> Effect"

So even activate abilities are payment powers.

Not all activate abilities are. Like you say, only those with --> are.

all activated powers will have an arrow after it luffy.

I'd like to see an example otherwise.

Ok, maybe you are right. Some of them do not appear directly after the activate word, they have other payment coming into it. Thats when I do not see the arrow after the activate word. However, there may be some in the future that will not have the arrow.

always true, though it would take alittle bit of new jazz in the rule book, it is always a possibility.

and I understand how the Arrow not being right after the word "activate" could make it seem different.

Just to clarify, activated abilities are a subset of payment powers. So if someone had Scarlet Witch, Wanda Maximoff in play and his/her opponent used roy, that person would lose 5 END. But if he/she used Red Star's pay 1 resource point effect (a payment power) then the person would not lose END from Scarlet Witch. However the new Avengers Scarlet Witch would stop both Red Star and Roy from using their abilities.

all very much correct.

Activated abilities are a subset of payment powers. so all activated powers are payment powers, but not all payment powers are activated powers (alittle SAT like action for you.)

Bhood scarlet witch will punish roy but not redstar like you said.

and the new one can prevent both of them, as can cards like repulser ray.

But don't forget about the Chain, they can dodge such restrictions.

That's why Scarlet witch is so cool actually. since each activation of her power only cost a discard. every time they try to activate, i'm pretty sure you can just discard another card to try to nullify their power.

Though I don't know if saying payment powers can't be used will actually remove such powers off of the chain...

Just becuse it's not included here, Evasion is also a payment power.

true. a very sad truth for the already bleak future of evasion.

yea, don't try to evade against Avengers decks! But the 4-drop Spidey helps them out a bit.

The new Scarlet Witch's power works in a manner akin to Bad Press. It cannot stop an effect already played, so it doesn't negate anything. It merely prevents effects from being added in the future.

If you add her power to the chain, and the chain resolves in reverse, why can you use her power in response to something?