4. Building a Transaction for a Market Order

/**
 * @notice Spends to take a list of orders
 * @param book_id The id of the book to take from
 * @param limit_price The maximum price to take at
 * @param base_amount The amount of base asset to spend
 * @param min_quote_amount The minimum amount of quote asset to receive
 * @param hook_data Additional data to pass to the hook
 * @param deadline The deadline for the actions
 */
fn spend(
    ref self: TContractState,
    book_id: felt252,
    limit_price: u256,
    base_amount: u256,
    min_quote_amount: u256,
    hook_data: Span<felt252>,
    deadline: u64
);

Similar to getExpectedOutput, if you want to set unlimited slippage, simply set the limitPrice parameter to 0.