To answer this question properly, we must know what you mean by "modest."
In internet advertising, 1% response from an ad is considered good.  3% is fantastic.  In the case of Safemail lists, this is the number that even look at your ad.  1% of them might click through and sign up as a PSA.  That says that you need to put the SFI spash page or an ad in front of at least 1 million people a day to get 100 PSA.
The question then becomes how to get an SFI ad in front of 1 Million people a day on a modest budget.  My answer to that one is that it cannot be done. It is impossible.
To get 100 PSA from the vendors is over $100, and they do not promise to deliver in a day.  To get 30 days worth of 100 PSA contracts, you would have to buy 30 contracts.  That is a cool $3,000 which I do not think meets the definition of a modest budget.
Now, if you have lots of computers and a large family, it might be possible to get them sending to safelists and surfing the click surf sites to generate a LOT of hits to a splash page, but you would run up against the 1 Million credits a day again.  Even at 10 seconds per credit - that is a heck of a lot of surfing on a lot of click surf sites.  That is also a lot of safelists and earning credits at those safelists.  Even though a lot of safelists give you 1,000 impressions upon joining, you have to earn by actions or wait a long time before you can mail again - and joining enough of them as a paid member would quickly drain even a modest budget.
I think you need to change your question to: How can I get 5 EAs and train them to each get 5 EAs in less than a year.  That is what your goal should be: Duplication.  That is what will get you to STL and GTL and enough VP matching to get a decent monthly check.
                                            
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                                        To answer this question properly, we must know what you mean by "modest."
In internet advertising, 1% response from an ad is considered good.  3% is fantastic.  In the case of Safemail lists, this is the number that even look at your ad.  1% of them might click through and sign up as a PSA.  That says that you need to put the SFI spash page or an ad in front of at least 1 million people a day to get 100 PSA.
The question then becomes how to get an SFI ad in front of
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