Sea Monster of Theseus MP17-EN231 Price Guide
Yu-Gi-Oh! · YuGiOh 2017 Mega-Tin Mega Pack · Released 2017
Sea Monster of Theseus MP17-EN231 (YuGiOh 2017 Mega-Tin Mega Pack) is currently worth $16.49 raw (near mint) and $164 in PSA 10 (as of Sep 13, 2026). Values come from the PriceCharting price guide and are refreshed weekly. Grading is the single biggest value lever — check the raw-to-PSA-10 gap below, then scan your copy to see if its centering makes the grade.
Current prices
Raw (ungraded)
| Ungraded | $16.49 |
Graded — grade ladder
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Last updated 2026-09-13 · Source: the PriceCharting price guide
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Price history
Is it worth grading?
Worth grading — even a PSA 9 beats raw
A PSA 10 Sea Monster of Theseus MP17-EN231 sells for $164 against $16.49 raw: a $148 spread, 9.9× the ungraded price. Even a PSA 9 ($81.96) clears the raw price after an economy-tier ~$25 fee, so a near-miss still comes out ahead. Centering is the usual reason a clean copy misses the 10 — measure it before you submit.
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Sea Monster of Theseus MP17-EN231 — frequently asked
How much is Sea Monster of Theseus MP17-EN231 (YuGiOh 2017 Mega-Tin Mega Pack) worth?
As of Sep 13, 2026, Sea Monster of Theseus MP17-EN231 (YuGiOh 2017 Mega-Tin Mega Pack): an ungraded near-mint copy sells for about $16.49, a PSA 10 sells for about $164, a PSA 9 for about $81.96. Values come from the PriceCharting price guide and are refreshed weekly.
How much is a PSA 10 Sea Monster of Theseus MP17-EN231 worth?
As of Sep 13, 2026, a PSA 10 (Gem Mint) Sea Monster of Theseus MP17-EN231 (YuGiOh 2017 Mega-Tin Mega Pack) sells for about $164, compared with $16.49 for a raw near-mint copy.
Is Sea Monster of Theseus MP17-EN231 worth grading?
A PSA 10 Sea Monster of Theseus MP17-EN231 sells for $164 against $16.49 raw: a $148 spread, 9.9× the ungraded price. Even a PSA 9 ($81.96) clears the raw price after an economy-tier ~$25 fee, so a near-miss still comes out ahead. Centering is the usual reason a clean copy misses the 10 — measure it before you submit.
Is Sea Monster of Theseus MP17-EN231 going up or down in value?
Sea Monster of Theseus MP17-EN231 (YuGiOh 2017 Mega-Tin Mega Pack) is down 6% over the last 30 days (PSA 10 market). Short-term moves on individual cards are noisy — check the price history above for the trend.
Where do these Yu-Gi-Oh! card prices come from?
Prices are the PriceCharting price guide, refreshed weekly. Raw values reflect near-mint (NM) ungraded copies; graded values are per grading company and grade.