IP management in a startup

The answer does vary depending on the type of product/market. For example, if you are pharma-based and have a novel compound, then when you have funds to put aside, I would invest in patent protection. There are a some lawfirms that offer startups patent assistance and will have an agreement to defer costs until the startup has received new or additional funding.

In general, for any startup or company. I recommend securing the brand (company brand or product brand) as soon as practical. This is generally done with a trademark filing which is a lot cheaper than patent filings. I rely heavily on trademark registrations for brand enforcement purposes. You can also file the trademarks yourself or with a IP consultant or IP/trademark attorney. I definitely recommend filing patents thru a skilled patent attorney. In addition, you can file copyrights on logos and other works. Copyright filings are also cost-effective. Finally, lock-up (obtain) your domain name, your social media and b2b online marketplace handles. These can be a lot harder to recover after the brand launches (and generally the cost of recovery can be 3-5K in legal fees or purchase if no fair use claim).
So on limited funds, I would secure the brand and have a trademark filing(s) (US is about $500 -$1000 per class filing through grant (without an attorney, a clearance search is anywhere from $250-$1500). Depending on the technology, I would look to find options on patent protection funding.