There are many free apps that can be used for practice purposes. Take a look at the ones below and consider using them with your smart device. You could also search you app store as there might be a tuner or metronome you would like better.
Tuners
Bandmate Tuner- This one is great because it shows the note on the staff for your instrument.
Tonal Energy Tuner- This tuner is visually better, but the cost is $4. It has a metronome built in so if you are looking for one app for everything this would be good.