Evading arrest is a Class "a" misdemeanor if it's a first time evading on foot. The punishment range is up to a year in jail and up to a $4000 fine. If you've previously been convicted of evading on foot then the offense is a state jail felony. State jail felony punishment range is 6 months to 2 years in the state jail and up to $10,000 fine.
If it's a second offense and you've been convicted of two prior state felonies, then it could be a third degree felony with a punishment range of 2 to 10 years in prison and up to a $10,000 fine.
As with any charge, if you have a clean record, it's important to try to get your case reduced or get a disposition that does not involve a conviction. In Travis County, there is deferred adjudication, Pretrial diversion and deferred prosecution at the misdemeanor level available for many first time offenders. Successfully completing a deferred adjudication (basically probation without a conviction) allows you to get your record sealed. Successfully completing Pretrial diversion or deferred prosecution allows you to get your record sealed.