If you start talking about co-located or self hosted services, the mitigation strategies are very different.
Assuming you can find yourself a transit provider that supports BGP flowspec updates (many don't, sadly), you can do this fairly cheaply. You'd obviously want some level of support from a network tech that knew what they were doing, but it's not insurmountable.
There's a bunch of other options available too.
This sort of thing is one of the downwsides of having your infrastructure managed by someone else. If things go wrong and your provider doesn't feel incentivised enough to help you out, there's a lot less you can do about it, other than just pay whatever sum they demand.
Assuming you can find yourself a transit provider that supports BGP flowspec updates (many don't, sadly), you can do this fairly cheaply. You'd obviously want some level of support from a network tech that knew what they were doing, but it's not insurmountable. There's a bunch of other options available too.
This sort of thing is one of the downwsides of having your infrastructure managed by someone else. If things go wrong and your provider doesn't feel incentivised enough to help you out, there's a lot less you can do about it, other than just pay whatever sum they demand.