BUENOS AIRES, Aug 15 (Reuters) - Argentina's monthly inflation rate stood at 6.3% in July, the country's statistics agency said on Tuesday, well below forecasts of a 7.1% jump, though analysts said it was expected to heat up again in August amid market turbulence.

The South American nation is battling its worst inflation since the early 1990s, with annual price rises at 113.4% through July, slightly down versus a month earlier. The rise in costs saps wages and savings and has left four-in-10 people under the poverty line.

The rapid price rises, which see retail and input costs constantly hiked, are playing a key role in the presidential election race ahead of an Oct. 22 general vote, with a far-right libertarian candidate riding a wave of voter anger.

"It's unsustainable. I really don't know how this is going to continue from here to October or in the future," said Alberto Acosta, a 47-year-old salesman, saying the price of his truck insurance had been hiked 35% to 26,000 pesos ($74.30).

"As a laborer, traveling every day, it's bad, you can't make ends meet," he said.

Annual inflation is expected to 141% by the end of the year, the latest central bank analyst poll estimates, but could rise further after a near 20% devaluation of the peso currency on Monday amid a market sell-off, which eased on Tuesday.

In a bid to ease the economic crisis, the country's central bank hiked the benchmark interest rate to 118% on Monday and let the peso currency, held in check by capital controls, slide sharply to a fixed 350 per dollar until the October vote.

That is being contested in a three-way race between outsider libertarian Javier Milei, who won the largest vote share in a Sunday primary, conservative Patricia Bullrich and economy minister Sergio Massa from the governing center-left Peronist coalition.

Argentina's government also said earlier on Tuesday it is in talks with the country's meat sector to cap domestic prices. Argentines are one of the world's top per capita consumers of beef, which makes its price politically sensitive.

Lautaro Moschet, economist at consultancy Fundación Libertad y Progreso, said he expected inflation to speed up in August to around 9.3%, after the recent peso devaluation and additional controls on access to dollars.

"For August we expect a strong acceleration," he said.

Nestor Varela, 62, said there seemed little hope that politicians would - or could - fix the issue any time soon.

"The issue of inflation really hits your wallet," he said, adding the big question mark was whether the government or big businesses would "really commit themselves to the task of bringing inflation down". ($1 = 349.9500 Argentine pesos)

(Reporting by Hernan Nessi; Writing by Carolina Pulice; Editing by Sarah Morland, Aurora Ellis and Deepa Babington)