All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
What you mentioned in your question is not considered outbidding, but it is like taking more than one offer as what the Prophet, sallallaahu ‘alayhi wa sallam, did. It was narrated on the authority of Anas that the Prophet, sallallaahu ‘alayhi wa sallam, once asked: "Who buys these (two items)?’ One man said, ‘I would buy them for one dirham,’ and the Prophet, sallallaahu ‘alayhi wa sallam, said: ‘Who offers a higher price?’ He said this twice or thrice." [At-Tirmithi: Hasan]
As for trying to know the offers presented by others in order to offer lesser prices, if you know this without spying, it would be alright. However, if you obtain this information through spying, this will be impermissible as Allaah The Almighty Says (what means): {And do not spy} [Quran 49:12]
Allaah Knows best.