Replace 128K with the rate you would like. Rate is in Bytes, K for kilobytes M for megabytes.
More info from the man pages
--limit-rate=amount Limit the download speed to amount bytes per second. Amount may be expressed in bytes, kilobytes with the k suffix, or megabytes with the m suffix. For example, --limit-rate=20k will limit the retrieval rate to 20KB/s. This is useful when, for whatever reason, you don't want Wget to consume the entire available bandwidth. This option allows the use of decimal numbers, usually in conjunction with power suffixes; for example, --limit-rate=2.5k is a legal value. Note that Wget implements the limiting by sleeping the appropriate amount of time after a network read that took less time than specified by the rate. Eventually this strategy causes the TCP transfer to slow down to approximately the specified rate. However, it may take some time for this balance to be achieved, so don't be surprised if limiting the rate doesn't work well with very small files.
The wget tool is an extremely useful command that allows you to download files from websites from the command line. Before you begin you should make sure you have Xcode installed. If you don’t, just download it from the App Store, its free.
To install wget on your mac you first need to download the source code from here. Next you need to extract the tarball. You can do this by double clicking the file in Finder or you can run the following command in the terminal
tar -zxvf ~/Downlaods/wget-1.14.tar.gz
Run the rest of these commands in the Terminal app.
Next we will cd into the directory.
and finally install it.
sudo make install
And of course make sure it works.
Congratulations, you have successfully compiled wget from source.