Over the last few months, high competition and the limited housing stock for sale have brought double-digit annual gains to home prices. That has locked out many buyers, particularly first-time home buyers, or forced them to stretch their budgets to the maximum.

Amid those dynamics, the median price of an existing home reached $356,700 in August—a nearly 15% uptick compared to a year earlier, according to the National Association of REALTORS®.

Lately, more inventory is coming onto the market, but first-time buyers are still struggling to afford today’s higher home prices and the costs of homeownership.

First-time buyers comprised 29% of sales in August—they usually make up about 40% of the housing market, according to NAR.

In general, buyers are typically in good financial shape. But many first-time buyers in particular have to keep their eyes on their budget to afford homeownership. Overextending themselves can lead to regret and financial hardship later on. Nearly two-thirds—or 64%—of millennials, aged 25 to 40, say they have at least one regret about purchasing their current home, according to a Bankrate poll from earlier this year. The top regrets are that maintenance, mortgage, and other costs are too high. Thirteen percent believe they overpaid for their property.

To feel more prepared, creating a budget and considering all the costs of homeownership are essential, financial experts say.

Tackling Buyer Remorse

The typical first-time home buyer makes a 7% down payment, on average, on a home purchase, according to NAR data. But some loan offerings may allow them to put down much less, like 3% or 3.5%, or even 0% with loans through the Department of Veterans Affairs, for those who are eligible.

After calculating the down payment, first-time buyers should factor in expenses like property taxes, homeowners insurance (which averages about $1,000 a year but can vary greatly), association fees, utilities, and maintenance costs.

“Something may break once you are in the home or you may want to decorate it or change the finishes within the home,” Jessica Lautz, NAR’s vice president of demographics and behavioral insights, told CNBC.

About 23% of buyers waived inspections in August, according to NAR, but that can lead to unexpected, expensive repairs. “That is the biggest budget buster to me,” Jacqueline Cooper, president and CEO of Financial Education Associates in Dorchester, Mass., told CNBC. “These are things we don’t notice and we don’t have the experience to determine if this is an OK thing or not.”

Another big expense buyers need to prepare for is closing costs. Those include costs like the appraisal, title insurance, credit reports, loan origination fees, and more that first-time home buyers ought to brace for. They can add up to between 2% to 5% of the home price and are due at closing.