This move was not very popular as it made starter packs next to worthless (except, of course, to actual newbies) and killed the value of those rares (their alternate versions included)
"Pokemon of the Day: Houndour (#228)"
Similarly, its hard for a seller to generalize and say that theyre selling an MP Underground Sea for a percentage of TCG low, without knowing what the difference between the cheapest MP and cheapest LP listing is
The easiest thing to do to remedy this was cut the Monolith for another, less combo-y rock
Before heading back there, you might want to grab the TM35 (Sleep Talk) and Max Ether here, as well as a quick dash upstairs to the department store basement, where you can find the Amulet Coin, Ultra Ball, Ether and Burn Heal
Grading costs $25-100+ per card, so the potential value increase must justify the expense and risk of getting a lower grade than expected