Here are some examples of assistance AWS provides startup companies.
AWS Activate is a program specifically tailored toward assisting startups in their AWS journey. Enrolling in this program provides exclusive benefits, some of which include credits to offset the cost of usage and technical support. As of November 2021, you can get $1000 in credits. You can apply for the program here: https://aws.amazon.com/activate/
If you are looking for additional support as a startup, consider applying for Startup of the Year. As of November 2021, you can get $5000 in credits: https://www.startupofyear.com/application