You can buy caesar sauce in Jumbo (Or indeed in many less prestigious places) for just over 20 pesos, however it isn't difficult to make your own fresh version and all the ingredients are very easy to get hold of in BA (Home made sauce won't keep past a day or two though).
Clean the shells of some fresh eggs, use the yolks, add garlic, black pepper, a little salt, parmigiana, a splash of salsa inglesa, lemon juice, maybe some white wine and add olive oil whilst mixing (Better yet mortar it in a petzel) until the consistency you like is reached.
Play around with personal portion sizes before you start doing it in front of your guests at the table when you have them round for dinner. The ratio is really easy to adjust and it takes less than 2 minutes when you have the ingredients in front of you.
Add anchovies from the deli for the more common style or grill some jamon crudo and chop it finely if you are wanting the bacon bits experience that is common (and lovely) in North America.
Granted initially it costs more than the bottled stuff, but freeze that parmigiana and make sure you adjust your budget for a slight increase in your weekly purchases (depending on how often you eat it) and you've got a very tasty, cheap, home made and, depending upon your guests, potentially spectacular party piece.
Since I've moved here I've been making all the stuff I'd normally buy in back home.
If in doubt, check out YouTube for various people's videos on recipes - it's a bit hit and mix but you'll find there are plenty enough out there to sate any appetite. That, with many failures and attempts, is how I learned and it's fun as well as healthier.
