These are spiffy old coins from Buenos Aires in Argentina. They were minted only in 1822 and 1823, thereafter replaced with national (Banco Nacional) coinage. They carry respectable catalog values:
worn: $2 US dollars approximate catalog value
average circulated: $25
well preserved: $60
fully uncirculated: $150
Both dates (1822 and 1823) are worth about the same. However, there is a rare variation that is worth much more than the values above. One decimo coins with medal alignment are worth about five times the values above, which are for 'normal' coins with coin alignment.
To find out if you have medal or coin alignment, hold the coin between your thumb and forefinger with the rising sun at the top. Your thumb should be underneath the coin and your forefinger should be just above the rising sun. Now turn the coin like you are turning the pages of a book, from right to left. If the date and BUENOS AYRES inscriptions are up-side down, you have normal coin alignment. But, after turning, the inscriptions are right-side up, you have rare medal alignment.
Hope you have the good one!