Fees and spread
How we charge fees, why the price you see already includes them, and what the bid/ask spread tells you.
Buying Yes at 47¢ costs you exactly 47¢ — there's no separate fee tacked on at checkout. Fees are taken from the outcome shares delivered to you: you pay full price for the share, but the share itself is a small percentage smaller than you'd otherwise get. The net effect is the same; the design is just cleaner and means the displayed price is the price you trade at.
Why the spread matters
The spread is the gap between the highest bid (someone offering to buy Yes) and the lowest ask (someone offering to sell Yes). A 1¢ spread (47/48¢) is very liquid — you'll get filled fast and close to the mid-price. A 10¢ spread (40/50¢) is thin — large orders may move the price significantly.
Spread weighting
Fees scale with how "informative" a trade is. Trading at 5¢ or 95¢ — the extremes — moves your edge a lot per dollar, but the fee is small in absolute terms because you're paying very few cents per share. Trading at 50¢ has the biggest spread weighting because you're in the most uncertain region. The math here matches Polymarket's so cross-platform spreads behave the same.