No we cannot suggest anything because you did not put a real location in your profile. Go put a real location in your profile.
In the US I think the cheapest option is a fat battery model Riva 510. Liberty-Flights.com, click the 20% off, then look at Riva 510 Lite Bundle - under $30 for 2 complete Rivas. You will also need lots of
eliquid and I recommend you get a drip tip and get the precut blue foam stuffing fpr 510 carts for under $1 at strictlyejuice.com
It is more pleasant to use Boge cartomizers on it, but you don't want to spend money and they are a recurring expense. Used properly, a cartomizer will not dump all of the juice in your mouth, they hold more than a cart, need juice added less often, and are just more pleasant to use. But they have limited lives as the performance decreases over 5-14 days. Only some people succeed at cleaning and drying and ever getting more good use out of them. They are meant to be disposable. using cart + atomizer instead means the carts can last a long time with cleaning/drying/restuffing. The atomizer is what you need spares of and they may need periodic cleaning.
If you do not live in the US then I don't know what is the cheapest good suggestion for you.
