Health insurance shoppers face a new deadline, rising prices and fewer options for help as the Affordable Care Act’s main enrollment window for 2018 coverage opens Wednesday.

The federal law created state-based marketplaces in which people can buy coverage with help from an income-based tax credit.

Experts say consumers should avoid last-minute shopping. The law’s enrollment window closes Dec. 15 in most states, and websites that process the applications tend to bog down near the deadline. Last year, shoppers had until late January to make their choice.

The price of coverage is climbing more than 10 percent in many markets, and funding cuts may leave shoppers with fewer options for help selecting a plan.

The Obama-era law survived congressional attempts to dismantle it earlier this year.