Arial with Helvetica in action on titanichistory.tilda.ws

Under the hood

.content-1 { font-family: Arial, Arial, sans-serif; font-size: 24px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 22px; text-transform: none; color: #1E1E1E; }
.content-2 { font-family: Arial, Arial, sans-serif; font-size: 20px; font-style: normal; font-weight: 400; letter-spacing: normal; line-height: 28px; text-transform: uppercase; color: #1E1E1E; }
.content-3 { font-family: Helvetica, Arial, sans-serif; font-size: 90px; font-style: normal; font-weight: 400; letter-spacing: normal; line-height: 99px; text-transform: none; color: #1E1E1E; }

Arial is available from Fonts.com and MyFonts.