I would like a "repeater" better than looked at cost than one that mentions a specific card. Like:
Prince's Court
Cost: 6
You may choose an Action card from your hand costing less than $6 and play it three times.
(It could be used successfully with itself if there are price-changing cards around.)
Or even a differential effect like
Prince's Court
Cost: 6
You may choose an Action card from your hand and play it.
If that card costs less than $6, play it again.
If that card costs less than $5, play it once more.
If that card costs less than $4, play it once more.