Merchant Scroll
Oracle Text
Search your library for a blue instant card, reveal that card, and put it into your hand. Then shuffle your library.
Card Rulings
10/4/2004 Because the “search” requires you to find a card with certain characteristics, you don’t have to find the card if you don’t want to.
Homelands had 8-card booster packs, with 6 cards from one 121-card (C) sheet, and 2 card from the other 121-card (U) sheet. The C-sheet had 50 C2 cards and 21 C1 cards on it, which just means those cards appeared on the sheet 2 or 1 times each. (50x2 + 21 = 121) Merchant Scroll was one of the C1 cards. The U-sheet had 25 U3s and 46 U1s. (25*3 + 46 = 121)
A C1 card appeared once on the C-sheet, so had a 1/121 chance of appearing for each C-card included in the booster. Because of the 6-2 breakdown, (6 C-cards & 2 U-cards) this means that a C1 like Merchant Scroll had a 4.96% of appearing per booster. (1/121 * 6 = 0.0496) U3s, which are widely accepted as uncommons, had that exact same chance. (3/121 * 2 = 0.0496)
More detail here:
http://www.mtgsalvation.com/forums/the-game/casual-related-formats/paper-pauper-peasant/177219-casual-paper-pauper-peasant-forum-rules#c16