With AWS Lambda, you pay only for what you use. You are charged based on the number of requests for your functions and the time your code executes. AWS Lambda is now generally available. The AWS Free Tier includes 1 million free requests and up to 3.2 million seconds of compute time per month with AWS Lambda.
To export data from Excel to a text file, use the Save As command. Delimited text files (.txt), in which the TAB character (ASCII character code 009) typically separates each field of text. Comma separated values text files (.csv), in which the comma character (,) typically separates each field of text.
What is CSV? The comma-separated values (CSV) format is a widely used text file format often used to exchange data between applications. It contains multiple records (one per line), and each field is delimited by a comma. Wikipedia has a good explanation of the CSV format and its history.