why money was exchanged when it is was marriage

[BumbleB]

You didn't necessarily have to be wealthy to marry by Licence.  I have a Joiner/Carpenter in 1767 (60+ marrying for the third time to a lady of 25), a Bookbinder in 1812, a Bookseller and Stationer in 1816.  A farmer who eventually got round to marrying the mother of his four children in 1831 (I suspect almost immediately after his mother died  )  All of these taking place in Yorkshire.

Another reason put forward for marrying by Licence was that the parties did not wish their intention to marry to be common knowledge within the parish/es. 

[jaybelnz]

Thanks BumbleB for clarifying that!

[stanmapstone]

A Licence was popular because it had the advantage of relative speed and secrecy, and facilitated a marriage in Lent when banns should not have been called. It was also favoured by those with rude surnames in order to avoid titters when the banns were read out.
For instance the marriage of Thomas Titty to Pleasant Grant in Margate on 17th November 1754 (March Family Tree Magazine, page 15)

Stan

[Guy Etchells]

As I understand it, the £500 would only have to be paid if the marriage did not take place.

A Bond and Allegation was only used in conjunction with a Marriage Licence, which meant that the couple did not have/wish to wait for the Banns to be read over 3 consecutive weeks.

No this is a common misconception about bonds.

The bond was a form of insurance for the clergyman who conducted the marriage.
It comes in two parts the obligation and the condition.
see
http://anguline.co.uk/cert/bond.jpg

The obligation sets out the contact between the parties who will pay and the person who will be paid, plus the sum to be paid if the marriage is unlawful.

The second part, the condition, indemnifies or saves harmless the official who carries out the marriage.

If the marriage did not take place then nothing had to be paid it was only if the marriage was unlawful that the money had to be paid.

Cheers
Guy

[BumbleB]

Many thanks, Guy, for the clarification with regards to Bond and Allegation. 

[stanmapstone]

The key phrase in my example at http://www.rootschat.com/forum/index.php/topic,438148.msg3016813.html#msg3016813 is
may lawfully solemnize marriage together and in the same afterwards lawfully remain.

Stan

[Suzy W]

Thank you so much. 
It was the first time I had ever came across this kind of document. Very interesting.  Almost like a bounty on one's head, so you better have to show up or else.

Thanks Again
Suzy W