What would you like done?
A plugin that would create the necessary tables in the database holding structured data (in our case, sales orders and fields related to each order).
When a topic is created in a category with this turned on, it will use an HTML-based input form to collect such data. Then the first post should render as a special format displaying the structured data.
Edits to the first post should bring up the input form to allow modification of the data plus persisting the changes.
Each topic is then tied to one such recordset of structured data.
Hopefully allowing full-text search for texts inside the data.
When do you need it done?
For most software the answer is… “Yesterday”… 
Realistically, a month to a couple of months is OK. Sooner than later though.
What is your budget, in $ USD that you can offer for this task?
Negotiable. Depending on how much functionalities will be included.
If it is truly basic, then maybe $1000-2000.
More functionalities and/or integration go up from here. Max $5000 I’d say, unless it does something great.