There is only one Hell and one Paradise. However, within Paradise there are many levels, the highest being Firdaws. However, there is no agreement or knowledge of the number of levels though there are reports from scholars saying the levels are equal to the number of verses in Qur'an (Al-Targheeb wa’l-Tarheeb, 2/228)but it is still under discussion. However, there are several hadiths saying that there are levels of Paradise.
The Prophet (saw) said, narrated by al-Bukhâri from Abû Hurayrah "
...Paradise has one hundred levels which Allâh has reserved for the
mujâhidîn who fight in His Cause and the distance between each of the
two grades is like the distance between the heavens and the earth. So
when you ask Allâh for something, ask for al-Firdaws which is the best
and highest part of Paradise. Above it is the throne of the Most
Merciful, and from it originate the rivers of Paradise".
[al-Bukhâri in as-Sahîh, Kitâb al-Jihâd, Bâb Darajat al-Mujâhidîn fi
Sabîlillâh, Fath al-Bâri, 6/11]
Ahmad, at-Tirmidhi, Ibn Mâjah and Ibn Hibbân reported from Abû Sa'îd that the Prophet (saw) said,
"The people in the higher levels will be seen by those below them as
if they were looking at a star rising on the horizon. Abû Bakr and
'Umar will be among them; what good people they are!" [Sahîh al-Jâmi'
as-Saghîr, 2/187, no. 2026]
Al Qurtubi said, these different levels are based upon the deeds of the occupants. Some are higher than the others.
And Allah knows the best.
More: al-Jannah wal an-Nâr-The Paradise and the Hellfire