The Belgium international has started the 2012/13 campaign in sparkling form, with the 24-year-old having played a pivotal role in guiding the Toffees into fourth spot.
Another goal and assist over the weekend helped Moyes' men past Sunderland and allowed them to cement their standing inside the UEFA Champions League places.
Having seen the likes of Wayne Rooney, Joleon Lescott and Mikel Arteta lured away from Goodison Park in the past there is a fear that Fellaini could soon be heading the same way, but Moyes has made it clear that anyone intending to bid for his prized asset will have to dig deep.
"They know where Felli is, they know where to come and watch him - they know as well that it will be a big price if they are interested," said the Scot.
"I'm not in the mood to keep the fight going all the time, because I've lost a few players now, but the ones we've lost - they've paid for.
"I think we've got to the stage at Everton where we say, 'Look, we've lost some really good players but I don't think it's stopped us from progressing the team'.
"We sold Lescott, we sold Arteta and we've all felt really down when we've lost those players but we've had to pick ourselves up and go and find other ones.
"The club will always be bigger than any player, any manager, and the players we've brought in are showing that."