The party had four MPs in the last parliament, but is hoping to make gains this election in an effort to mirror the SNP.
Their manifesto - entitled "Wales, It's Us" promises significant investment in infrastructure and the environment, as well as free social care.
The party also say a vote for them will be a vote for Wales to stay inside the European Union and build a “prosperous future”.
Environment and infrastructure
Plaid Cymru has promised a £20bn “green jobs revolution”, partly paid for by the UK government increasing capital investment for 10 years.
Plans would include significant investment in rail and bus travel, three tidal lagoons, a barrage and a new offshore wind farm. Also included is the construction of 20,000 green social houses.
Mr Price called on Wales to create its own national energy company, and said a new "green" industrial revolution would help tackle the threat of climate change.
According to Mr Price, the party would invest the £20bn over the next 10 years from a national reconstruction fund.
To help fund its plans Plaid Cymru is calling for Westminster to allocate an extra one per cent of GDP to its investment fund, allowing Wales to invest an extra £15bn.
It said it would also press the Treasury to raise Wales' borrowing limit from £1bn to £5bn, to reach the £20bn total for its green jobs promise.
The party would introduce the goal of making Wales carbon and single-use plastic free by 2030 and oppose the creation of new nuclear power sites.
Plaid Cymru have pledged an overhaul of the Welsh NHS with social care, staff numbers, mental health services and cancer treatment all improved.
Free social care would be provided at the point of need, along with extra investment in early intervention and preventative health care. Plaid Cymru estimate the additional social care provision would cost the Welsh government £300m a year.
An additional 1,000 doctors, 5,000 nurses and 100 dentists would be recruited and trained for the Welsh NHS.
They will also provide a five per cent increase in mental health expenditure every year for the next decade and work to improve cancer survival rates.
Plaid Cymru will recruit an extra 1,600 police officers, representing two extra officers per community.
Reform on drug laws would be pursued, with the party establishing a national commission to examine changing legislation on drug dependency.
Education and children
Spending on education would be increased, with an £300m per year going to schools and colleges across Wales. A structured plan of support for teachers would aim to reduce the number quitting the classroom.
A "fair deal for families" would offer universal free childcare for 40 hours a week, and a £35 a week payment for every child in a low income household, which they say will lift 50,000 children out of poverty.
Plaid Cymru would create a national housing service, which would borrow against rents.
They pledge to invest in environmentally sustainable affordable homes and rent relief for people who pay more than 30 per cent of their income on rent. As part of Plaid’s “green revolution”, the party has pledged the construction of 20,000 green social houses.
They would abolish the Vagrancy Act of 1842, which effectively criminalises rough sleeping.
Any VAT revenue generated in Wales would be kept in Wales. They would devolve air passenger duty, as has happened in Scotland.
The party will push for more powers over corporation tax rates in Wales and increase National insurance from two per cent to four per cent for high earners.
Mr Price said his party would fight to remain in the EU in a "final referendum".
When launching the manifesto he said: "We must defeat the negative, hope-crushing wrecking ball that is Brexit.
"And if you want the people to have their final say then we must encourage as many of them to say loudly and clearly in the days ahead this Brexit is not for us, it never was and never will be."
The party say a Welsh Government led by Plaid Cymru after the 2021 Welsh Assembly election would produce a self-determination Bill, aimed at a referendum on independence before 2030.
In his speech Mr Price said: "They say that our dream of an independent Wales is improbable, that our poverty is inevitable, well, this is the moment when the improbable beats what Westminster says is inevitable."
Defence and foreign policy
Plaid Cymru want the decision to go to war to require support from all four UK nations.