There are many factors to consider when you say, "My android is slow.":
1) Which Android phone are you using ?
2) What is the version of Android your phone is on ?
3) Are there any rogue apps, third party apps (other than Play Store) installed on your phone ? This may cause system instability & the "slow" part.
4) Have you disabled the unwanted pre-installed apps ? If not, this also leads to slow down of your phone.
If none of the above fits your query, then it's definitely the time to buy a better & latest Android phone.