The five artists who performed on Sunday's first live semi-final made their tracks available to download immediately after the show ended.
Duo Pepper & Piano, who were voted into the final, have had the most success with their self-penned track 'You Took My Heart', which is currently at number four on iTunes.
The song, which has been backed by Lily Allen on Twitter, is also expected to score high on the official midweek charts, which are revealed later today.
Writing yesterday on Twitter, popstar Allen said: "Pepper and Piano seem to be No.7 in iTunes chart today. Very good news, let's get it to No.1."
Daithi, who will also take part in the grand final, hip-hop group Flo Dem and electro outfit Legion of Many are also currently in the iTunes Top 100 chart. All money raised by the sales of tracks goes directly to the artists.
Must Be The Music's second live semi-final airs next Sunday at 7pm on Sky1.