Microsoft really wants startups to use its growing Azure public cloud. The tech giant’s latest ploy: offering $500,000 worth of hosting credits to startups in the high-profile Y Combinator accelerator.

Microsoft is also throwing in other goodies to interested startups in the Winter 2015 batch and later batches: three years of Office 365 application usage, access to Microsoft developer staff, a free year of CloudFlare services, and free DataStax enterprise services, according to a blog post today from Sam Altman, the accelerator’s president.

“We are happy to announce Microsoft will be giving $500,000 of free Azure hosting credit to YC startups in our Winter 2015 batch and future batches,” Altman wrote. “This is a big deal for many startups — it’s common for hosting to be the second largest expense after salaries.”

Many of the most popular cloud infrastructure providers, including Amazon Web Services and Google Cloud Platform, provide cloud credits to startups going through accelerators. Google gives away $100,000 in cloud credits to Y Combinator startups. Amazon, the leader in the public cloud market and a popular choice among startups, gives away as much as $15,000 to startups in Y Combinator and other accelerators through its Activate program.

So Microsoft’s move today looks like a challenge to its competitors. The question is whether startups already running on Amazon or Google, or other public clouds, or even their own data center infrastructure, will want to move to Azure.